node-mssql

Microsoft SQL Server client for Node.js

Supported TDS drivers:

• Tedious (pure JavaScript - Windows/macOS/Linux, default)
• Microsoft / Contributors Node V8 Driver for Node.js for SQL Server (native - Windows/Linux only)

Installation

npm install mssql

Quick Example

const sql = require('mssql')

async () => {
    try {
        // make sure that any items are correctly URL encoded in the connection string
        await sql.connect('mssql://username:password@localhost/database')
        const result = await sql.query`select * from mytable where id = ${value}`
        console.dir(result)
    } catch (err) {
        // ... error checks
    }
}

If you're on Windows Azure, add ?encrypt=true to your connection string. See docs to learn more.

Parts of the connection URI should be correctly URL encoded so that the URI can be parsed correctly.

Documentation

Examples

• Async/Await
• Promises
• ES6 Tagged template literals
• Callbacks
• Streaming
• Connection Pools

Configuration

• General
• Formats

Drivers

• Tedious
• Microsoft / Contributors Node V8 Driver for Node.js for SQL Server

Connections

• Pool Management
• ConnectionPool
• connect
• close

Requests

• Request
• execute
• input
• output
• pipe
• query
• batch
• bulk
• cancel

Transactions

• Transaction
• begin
• commit
• rollback

Prepared Statements

• PreparedStatement
• input
• output
• prepare
• execute
• unprepare

Other

• CLI
• Geography and Geometry
• Table-Valued Parameter
• Affected Rows
• JSON support
• Errors
• Informational messages
• Metadata
• Data Types
• SQL injection
• Known Issues
• Contributing
• 5.x to 6.x changes
• 4.x to 5.x changes
• 3.x to 4.x changes
• 3.x Documentation

Examples

Config

const config = {
    user: '...',
    password: '...',
    server: 'localhost', // You can use 'localhost\\instance' to connect to named instance
    database: '...',
}

Async/Await

const sql = require('mssql')

(async function () {
    try {
        let pool = await sql.connect(config)
        let result1 = await pool.request()
            .input('input_parameter', sql.Int, value)
            .query('select * from mytable where id = @input_parameter')
            
        console.dir(result1)
    
        // Stored procedure
        
        let result2 = await pool.request()
            .input('input_parameter', sql.Int, value)
            .output('output_parameter', sql.VarChar(50))
            .execute('procedure_name')
        
        console.dir(result2)
    } catch (err) {
        // ... error checks
    }
})()

sql.on('error', err => {
    // ... error handler
})

Promises

Queries

const sql = require('mssql')

sql.on('error', err => {
    // ... error handler
})

sql.connect(config).then(pool => {
    // Query
    
    return pool.request()
        .input('input_parameter', sql.Int, value)
        .query('select * from mytable where id = @input_parameter')
}).then(result => {
    console.dir(result)
}).catch(err => {
  // ... error checks
});

Stored procedures

const sql = require('mssql')

sql.on('error', err => {
    // ... error handler
})

sql.connect(config).then(pool => {
    
    // Stored procedure
    
    return pool.request()
        .input('input_parameter', sql.Int, value)
        .output('output_parameter', sql.VarChar(50))
        .execute('procedure_name')
}).then(result => {
    console.dir(result)
}).catch(err => {
    // ... error checks
})

Native Promise is used by default. You can easily change this with sql.Promise = require('myownpromisepackage').

ES6 Tagged template literals

const sql = require('mssql')

sql.connect(config).then(() => {
    return sql.query`select * from mytable where id = ${value}`
}).then(result => {
    console.dir(result)
}).catch(err => {
    // ... error checks
})

sql.on('error', err => {
    // ... error handler
})

All values are automatically sanitized against sql injection. This is because it is rendered as prepared statement, and thus all limitations imposed in MS SQL on parameters apply. e.g. Column names cannot be passed/set in statements using variables.

Callbacks

const sql = require('mssql')

sql.connect(config, err => {
    // ... error checks

    // Query

    new sql.Request().query('select 1 as number', (err, result) => {
        // ... error checks

        console.dir(result)
    })

    // Stored Procedure

    new sql.Request()
    .input('input_parameter', sql.Int, value)
    .output('output_parameter', sql.VarChar(50))
    .execute('procedure_name', (err, result) => {
        // ... error checks

        console.dir(result)
    })

    // Using template literal

    const request = new sql.Request()
    request.query(request.template`select * from mytable where id = ${value}`, (err, result) => {
        // ... error checks
        console.dir(result)
    })
})

sql.on('error', err => {
    // ... error handler
})

Streaming

If you plan to work with large amount of rows, you should always use streaming. Once you enable this, you must listen for events to receive data.

const sql = require('mssql')

sql.connect(config, err => {
    // ... error checks

    const request = new sql.Request()
    request.stream = true // You can set streaming differently for each request
    request.query('select * from verylargetable') // or request.execute(procedure)

    request.on('recordset', columns => {
        // Emitted once for each recordset in a query
    })

    request.on('row', row => {
        // Emitted for each row in a recordset
    })

    request.on('error', err => {
        // May be emitted multiple times
    })

    request.on('done', result => {
        // Always emitted as the last one
    })
})

sql.on('error', err => {
    // ... error handler
})

When streaming large sets of data you want to back-off or chunk the amount of data you're processing to prevent memory exhaustion issues; you can use the Request.pause() function to do this. Here is an example of managing rows in batches of 15:

let rowsToProcess = [];
request.on('row', row => {
  rowsToProcess.push(row);
  if (rowsToProcess.length >= 15) {
    request.pause();
    processRows();
  }
});
request.on('done', () => {
    processRows();
});

function processRows() {
  // process rows
  rowsToProcess = [];
  request.resume();
}

Pool Management

An important concept to understand when using this library is Connection Pooling as this library uses connection pooling extensively.

As one Node JS process is able to handle multiple requests at once, we can take advantage of this long running process to create a pool of database connections for reuse; this saves overhead of connecting to the database for each request (as would be the case in something like PHP, where one process handles one request).

With the advantages of pooling comes some added complexities, but these are mostly just conceptual and once you understand how the pooling is working, it is simple to make use of it efficiently and effectively.

The Global Connection (Pool)

To assist with pool management in your application there is the global connect() function that is available for use. As of v6 of this library a developer can make repeated calls to this function to obtain the global connection pool. This means you do not need to keep track of the pool in your application (as used to be the case). If the global pool is already connected, it will resolve to the connected pool. For example:

const sql = require('mssql')

// run a query against the global connection pool
function runQuery(query) {
  // sql.connect() will return the existing global pool if it exists or create a new one if it doesn't
  return sql.connect().then((pool) => {
    return pool.query(query)
  })
}

Here we obtain the global connection pool by running sql.connect() and we then run the query against the pool. We also do not close the pool after the query is executed and that is because other queries may need to be run against this pool and closing it will add an overhead to running the query. We should only ever close the pool when our application is finished. For example, if we are running some kind of CLI tool or a CRON job:

const sql = require('mssql')

(() => {
  sql.connect().then(pool => {
    return pool.query('SELECT 1')
  }).then(result => {
    // do something with result
  }).then(() => {
    return sql.close()
  })
})()

Here the connection will be closed and the node process will exit once the queries and other application logic has completed. You should aim to only close the pool once in your application, when it is exiting or you know your application will never make another SQL query.

Advanced Pool Management

In some instances you will not want to use the connection pool, you may have multiple databases to connect to or you may have one pool for read-only operations and another pool for read-write. In this instance you will need to implement your own pool management.

That could look something like this:

const { ConnectionPool } = require('mssql')
const POOLS = {}

function createPool(config, name) {
  if (getPool(name)) {
    throw new Error('Pool with this name already exists')
  }
  return POOLS[name] = (new ConnectionPool(config)).connect()
}

function closePool(name) {
  if (Object.prototype.hasOwnProperty.apply(POOLS, name)) {
    const pool = POOLS[name];
    delete POOLS[name];
    return pool.close()
  }
}

function getPool(name) {
  if (Object.prototype.hasOwnProperty.apply(POOLS, name)) {
    return POOLS[name]
  }
}

module.exports = {
  closePool,
  createPool,
  getPool
}

This helper file can then be used in your application to create, fetch and close your pools. As with the global pools, you should aim to only close a pool when you know it will never be needed by the application again; typically this will be when your application is shutting down.

Connection Pools

Using a single connection pool for your application/service is recommended. Instantiating a pool with a callback, or immediately calling .connect, is asynchronous to ensure a connection can be established before returning. From that point, you're able to acquire connections as normal:

const sql = require('mssql')

// async/await style:
const pool1 = new sql.ConnectionPool(config);
const pool1Connect = pool1.connect();

pool1.on('error', err => {
    // ... error handler
})

async function messageHandler() {
    await pool1Connect; // ensures that the pool has been created
    try {
        const request = pool1.request(); // or: new sql.Request(pool1)
        const result = await request.query('select 1 as number')
        console.dir(result)
        return result;
    } catch (err) {
        console.error('SQL error', err);
    }
}

// promise style:
const pool2 = new sql.ConnectionPool(config)
const pool2Connect = pool2.connect()

pool2.on('error', err => {
    // ... error handler
})

function runStoredProcedure() {
    return pool2Connect.then((pool) => {
        pool.request() // or: new sql.Request(pool2)
        .input('input_parameter', sql.Int, 10)
        .output('output_parameter', sql.VarChar(50))
        .execute('procedure_name', (err, result) => {
            // ... error checks
            console.dir(result)
        })
    }).catch(err => {
        // ... error handler
    })
}

Awaiting or .thening the pool creation is a safe way to ensure that the pool is always ready, without knowing where it is needed first. In practice, once the pool is created then there will be no delay for the next operation.

As of v6.1.0 you can make repeat calls to ConnectionPool.connect() and ConnectonPool.close() without an error being thrown, allowing for the safe use of mssql.connect().then(...) throughout your code as well as making multiple calls to close when your application is shutting down.

The ability to call connect() repeatedly is intended to make pool management easier, however it is still recommended to follow the example above where connect() is called once and using the original resolved connection promise. Repeatedly calling connect() when running queries risks running into problems when close() is called on the pool.

ES6 Tagged template literals

new sql.ConnectionPool(config).connect().then(pool => {
    return pool.query`select * from mytable where id = ${value}`
}).then(result => {
    console.dir(result)
}).catch(err => {
    // ... error checks
})

All values are automatically sanitized against sql injection.

Managing connection pools

Most applications will only need a single ConnectionPool that can be shared throughout the code. To aid the sharing of a single pool this library exposes a set of functions to access a single global connection. eg:

// as part of your application's boot process

const sql = require('mssql')
const poolPromise = sql.connect()

// during your applications runtime

poolPromise.then(() => {
  return sql.query('SELECT 1')
}).then(result => {
  console.dir(result)
})

// when your application exits
poolPromise.then(() => {
  return sql.close()
})

If you require multiple pools per application (perhaps you have many DBs you need to connect to or you want a read-only pool), then you will need to manage your pools yourself. The best way to do this is to create a shared library file that can hold references to the pools for you. For example:

const sql = require('mssql')

const pools = {}

// manage a set of pools by name (config will be required to create the pool)
// a pool will be removed when it is closed
async function getPool(name, config) {
  if (!Object.prototype.hasOwnProperty.call(pools, name)) {
    const pool = new sql.ConnectionPool(config)
    const close = pool.close.bind(pool)
    pool.close = (...args) => {
      delete pools[name]
      return close(...args)
    }
    await pool.connect()
    pools[name] = pool
  }
  return pools[name]
}

// close all pools
function closeAll() {
  return Promise.all(Object.values(pools).map((pool) => {
    return pool.close()
  }))
}

module.exports = {
  closeAll,
  getPool
}

You can then use this library file in your code to get a connected pool when you need it:

const { getPool } = require('./path/to/file')

// run a query
async function runQuery(query, config) {
  // pool will always be connected when the promise has resolved - may reject if the connection config is invalid
  const pool = await getPool('default', config)
  const result = await pool.request().query(query)
  return result
}

Configuration

const config = {
    user: '...',
    password: '...',
    server: 'localhost',
    database: '...',
    pool: {
        max: 10,
        min: 0,
        idleTimeoutMillis: 30000
    }
}

General (same for all drivers)

• user - User name to use for authentication.
• password - Password to use for authentication.
• server - Server to connect to. You can use 'localhost\instance' to connect to named instance.
• port - Port to connect to (default: 1433). Don't set when connecting to named instance.
• domain - Once you set domain, driver will connect to SQL Server using domain login.
• database - Database to connect to (default: dependent on server configuration).
• connectionTimeout - Connection timeout in ms (default: 15000).
• requestTimeout - Request timeout in ms (default: 15000). NOTE: msnodesqlv8 driver doesn't support timeouts < 1 second. When passed via connection string, the key must be request timeout
• stream - Stream recordsets/rows instead of returning them all at once as an argument of callback (default: false). You can also enable streaming for each request independently (request.stream = true). Always set to true if you plan to work with large amount of rows.
• parseJSON - Parse JSON recordsets to JS objects (default: false). For more information please see section JSON support.
• pool.max - The maximum number of connections there can be in the pool (default: 10).
• pool.min - The minimum of connections there can be in the pool (default: 0).
• pool.idleTimeoutMillis - The Number of milliseconds before closing an unused connection (default: 30000).

Complete list of pool options can be found here.

Formats

In addition to configuration object there is an option to pass config as a connection string. Two formats of connection string are supported.

Classic Connection String

Server=localhost,1433;Database=database;User Id=username;Password=password;Encrypt=true
Driver=msnodesqlv8;Server=(local)\INSTANCE;Database=database;UID=DOMAIN\username;PWD=password;Encrypt=true

Connection String URI

mssql://username:password@localhost:1433/database?encrypt=true
mssql://username:password@localhost/INSTANCE/database?encrypt=true&domain=DOMAIN&driver=msnodesqlv8

Drivers

Tedious

Default driver, actively maintained and production ready. Platform independent, runs everywhere Node.js runs. Officially supported by Microsoft.

Extra options:

• beforeConnect(conn) - Function, which is invoked before opening the connection. The parameter conn is the configured tedious Connection. It can be used for attaching event handlers like in this example:

require('mssql').connect(...config, beforeConnect: conn => {
  conn.once('connect', err => { err ? console.error(err) : console.log('mssql connected')})
  conn.once('end', err => { err ? console.error(err) : console.log('mssql disconnected')})
}})

• options.instanceName - The instance name to connect to. The SQL Server Browser service must be running on the database server, and UDP port 1434 on the database server must be reachable.
• options.useUTC - A boolean determining whether or not use UTC time for values without time zone offset (default: true).
• options.encrypt - A boolean determining whether or not the connection will be encrypted (default: true).
• options.tdsVersion - The version of TDS to use (default: 7_4, available: 7_1, 7_2, 7_3_A, 7_3_B, 7_4).
• options.appName - Application name used for SQL server logging.
• options.abortTransactionOnError - A boolean determining whether to rollback a transaction automatically if any error is encountered during the given transaction's execution. This sets the value for XACT_ABORT during the initial SQL phase of a connection.

More information about Tedious specific options: https://tediousjs.github.io/tedious/api-connection.html

Microsoft / Contributors Node V8 Driver for Node.js for SQL Server

Requires Node.js v10+ or newer. Windows/Linux only. This driver is not part of the default package and must be installed separately by npm install msnodesqlv8. To use this driver, use this require syntax: const sql = require('mssql/msnodesqlv8').

Extra options:

• beforeConnect(conn) - Function, which is invoked before opening the connection. The parameter conn is the connection configuration, that can be modified to pass extra parameters to the driver's open() method.
• connectionString - Connection string (default: see below).
• options.instanceName - The instance name to connect to. The SQL Server Browser service must be running on the database server, and UDP port 1444 on the database server must be reachable.
• options.trustedConnection - Use Windows Authentication (default: false).
• options.useUTC - A boolean determining whether or not to use UTC time for values without time zone offset (default: true).

Default connection string when connecting to port:

Driver={SQL Server Native Client 11.0};Server={#{server},#{port}};Database={#{database}};Uid={#{user}};Pwd={#{password}};Trusted_Connection={#{trusted}};

Default connection string when connecting to named instance:

Driver={SQL Server Native Client 11.0};Server={#{server}\\#{instance}};Database={#{database}};Uid={#{user}};Pwd={#{password}};Trusted_Connection={#{trusted}};

Connections

Internally, each ConnectionPool instance is a separate pool of TDS connections. Once you create a new Request/Transaction/Prepared Statement, a new TDS connection is acquired from the pool and reserved for desired action. Once the action is complete, connection is released back to the pool. Connection health check is built-in so once the dead connection is discovered, it is immediately replaced with a new one.

IMPORTANT: Always attach an error listener to created connection. Whenever something goes wrong with the connection it will emit an error and if there is no listener it will crash your application with an uncaught error.

const pool = new sql.ConnectionPool({ /* config */ })

Events

• error(err) - Dispatched on connection error.

---

connect ([callback])

Create a new connection pool. The initial probe connection is created to find out whether the configuration is valid.

Arguments

• callback(err) - A callback which is called after initial probe connection has established, or an error has occurred. Optional. If omitted, returns Promise.

Example

const pool = new sql.ConnectionPool({
    user: '...',
    password: '...',
    server: 'localhost',
    database: '...'
})

pool.connect(err => {
    // ...
})

Errors

• ELOGIN (ConnectionError) - Login failed.
• ETIMEOUT (ConnectionError) - Connection timeout.
• EALREADYCONNECTED (ConnectionError) - Database is already connected!
• EALREADYCONNECTING (ConnectionError) - Already connecting to database!
• EINSTLOOKUP (ConnectionError) - Instance lookup failed.
• ESOCKET (ConnectionError) - Socket error.

---

close()

Close all active connections in the pool.

Example

pool.close()

Request

const request = new sql.Request(/* [pool or transaction] */)

If you omit pool/transaction argument, global pool is used instead.

Events

• recordset(columns) - Dispatched when metadata for new recordset are parsed.
• row(row) - Dispatched when new row is parsed.
• done(returnValue) - Dispatched when request is complete.
• error(err) - Dispatched on error.
• info(message) - Dispatched on informational message.

---

execute (procedure, [callback])

Call a stored procedure.

Arguments

• procedure - Name of the stored procedure to be executed.
• callback(err, recordsets, returnValue) - A callback which is called after execution has completed, or an error has occurred. returnValue is also accessible as property of recordsets. Optional. If omitted, returns Promise.

Example

const request = new sql.Request()
request.input('input_parameter', sql.Int, value)
request.output('output_parameter', sql.Int)
request.execute('procedure_name', (err, result) => {
    // ... error checks

    console.log(result.recordsets.length) // count of recordsets returned by the procedure
    console.log(result.recordsets[0].length) // count of rows contained in first recordset
    console.log(result.recordset) // first recordset from result.recordsets
    console.log(result.returnValue) // procedure return value
    console.log(result.output) // key/value collection of output values
    console.log(result.rowsAffected) // array of numbers, each number represents the number of rows affected by executed statemens

    // ...
})

Errors

• EREQUEST (RequestError) - Message from SQL Server
• ECANCEL (RequestError) - Cancelled.
• ETIMEOUT (RequestError) - Request timeout.
• ENOCONN (RequestError) - No connection is specified for that request.
• ENOTOPEN (ConnectionError) - Connection not yet open.
• ECONNCLOSED (ConnectionError) - Connection is closed.
• ENOTBEGUN (TransactionError) - Transaction has not begun.
• EABORT (TransactionError) - Transaction was aborted (by user or because of an error).

---

input (name, [type], value)

Add an input parameter to the request.

Arguments

• name - Name of the input parameter without @ char.
• type - SQL data type of input parameter. If you omit type, module automatically decide which SQL data type should be used based on JS data type.
• value - Input parameter value. undefined ans NaN values are automatically converted to null values.

Example

request.input('input_parameter', value)
request.input('input_parameter', sql.Int, value)

JS Data Type To SQL Data Type Map

• String -> sql.NVarChar
• Number -> sql.Int
• Boolean -> sql.Bit
• Date -> sql.DateTime
• Buffer -> sql.VarBinary
• sql.Table -> sql.TVP

Default data type for unknown object is sql.NVarChar.

You can define your own type map.

sql.map.register(MyClass, sql.Text)

You can also overwrite the default type map.

sql.map.register(Number, sql.BigInt)

Errors (synchronous)

• EARGS (RequestError) - Invalid number of arguments.
• EINJECT (RequestError) - SQL injection warning.

---

NB: Do not use parameters @p{n} as these are used by the internal drivers and cause a conflict.

output (name, type, [value])

Add an output parameter to the request.

Arguments

• name - Name of the output parameter without @ char.
• type - SQL data type of output parameter.
• value - Output parameter value initial value. undefined and NaN values are automatically converted to null values. Optional.

Example

request.output('output_parameter', sql.Int)
request.output('output_parameter', sql.VarChar(50), 'abc')

Errors (synchronous)

• EARGS (RequestError) - Invalid number of arguments.
• EINJECT (RequestError) - SQL injection warning.

---

pipe (stream)

Sets request to stream mode and pulls all rows from all recordsets to a given stream.

Arguments

• stream - Writable stream in object mode.

Example

const request = new sql.Request()
request.pipe(stream)
request.query('select * from mytable')
stream.on('error', err => {
    // ...
})
stream.on('finish', () => {
    // ...
})

---

query (command, [callback])

Execute the SQL command. To execute commands like create procedure or if you plan to work with local temporary tables, use batch instead.

Arguments

• command - T-SQL command to be executed.
• callback(err, recordset) - A callback which is called after execution has completed, or an error has occurred. Optional. If omitted, returns Promise.

Example

const request = new sql.Request()
request.query('select 1 as number', (err, result) => {
    // ... error checks

    console.log(result.recordset[0].number) // return 1

    // ...
})

Errors

• ETIMEOUT (RequestError) - Request timeout.
• EREQUEST (RequestError) - Message from SQL Server
• ECANCEL (RequestError) - Cancelled.
• ENOCONN (RequestError) - No connection is specified for that request.
• ENOTOPEN (ConnectionError) - Connection not yet open.
• ECONNCLOSED (ConnectionError) - Connection is closed.
• ENOTBEGUN (TransactionError) - Transaction has not begun.
• EABORT (TransactionError) - Transaction was aborted (by user or because of an error).

const request = new sql.Request()
request.query('select 1 as number; select 2 as number', (err, result) => {
    // ... error checks

    console.log(result.recordset[0].number) // return 1
    console.log(result.recordsets[0][0].number) // return 1
    console.log(result.recordsets[1][0].number) // return 2
})

NOTE: To get number of rows affected by the statement(s), see section Affected Rows.

---

batch (batch, [callback])

Execute the SQL command. Unlike query, it doesn't use sp_executesql, so is not likely that SQL Server will reuse the execution plan it generates for the SQL. Use this only in special cases, for example when you need to execute commands like create procedure which can't be executed with query or if you're executing statements longer than 4000 chars on SQL Server 2000. Also you should use this if you're plan to work with local temporary tables (more information here).

NOTE: Table-Valued Parameter (TVP) is not supported in batch.

Arguments

• batch - T-SQL command to be executed.
• callback(err, recordset) - A callback which is called after execution has completed, or an error has occurred. Optional. If omitted, returns Promise.

Example

const request = new sql.Request()
request.batch('create procedure #temporary as select * from table', (err, result) => {
    // ... error checks
})

Errors

• ETIMEOUT (RequestError) - Request timeout.
• EREQUEST (RequestError) - Message from SQL Server
• ECANCEL (RequestError) - Cancelled.
• ENOCONN (RequestError) - No connection is specified for that request.
• ENOTOPEN (ConnectionError) - Connection not yet open.
• ECONNCLOSED (ConnectionError) - Connection is closed.
• ENOTBEGUN (TransactionError) - Transaction has not begun.
• EABORT (TransactionError) - Transaction was aborted (by user or because of an error).

You can enable multiple recordsets in queries with the request.multiple = true command.

---

bulk (table, [options,] [callback])

Perform a bulk insert.

Arguments

• table - sql.Table instance.
• options - Options object to be passed through to driver (currently tedious only). Optional. If argument is a function it will be treated as the callback.
• callback(err, rowCount) - A callback which is called after bulk insert has completed, or an error has occurred. Optional. If omitted, returns Promise.

Example

const table = new sql.Table('table_name') // or temporary table, e.g. #temptable
table.create = true
table.columns.add('a', sql.Int, {nullable: true, primary: true})
table.columns.add('b', sql.VarChar(50), {nullable: false})
table.rows.add(777, 'test')

const request = new sql.Request()
request.bulk(table, (err, result) => {
    // ... error checks
})

IMPORTANT: Always indicate whether the column is nullable or not!

TIP: If you set table.create to true, module will check if the table exists before it start sending data. If it doesn't, it will automatically create it. You can specify primary key columns by setting primary: true to column's options. Primary key constraint on multiple columns is supported.

TIP: You can also create Table variable from any recordset with recordset.toTable(). You can optionally specify table type name in the first argument.

Errors

• ENAME (RequestError) - Table name must be specified for bulk insert.
• ETIMEOUT (RequestError) - Request timeout.
• EREQUEST (RequestError) - Message from SQL Server
• ECANCEL (RequestError) - Cancelled.
• ENOCONN (RequestError) - No connection is specified for that request.
• ENOTOPEN (ConnectionError) - Connection not yet open.
• ECONNCLOSED (ConnectionError) - Connection is closed.
• ENOTBEGUN (TransactionError) - Transaction has not begun.
• EABORT (TransactionError) - Transaction was aborted (by user or because of an error).

---

cancel()

Cancel currently executing request. Return true if cancellation packet was send successfully.

Example

const request = new sql.Request()
request.query('waitfor delay \'00:00:05\'; select 1 as number', (err, result) => {
    console.log(err instanceof sql.RequestError)  // true
    console.log(err.message)                      // Cancelled.
    console.log(err.code)                         // ECANCEL

    // ...
})

request.cancel()

Transaction

IMPORTANT: always use Transaction class to create transactions - it ensures that all your requests are executed on one connection. Once you call begin, a single connection is acquired from the connection pool and all subsequent requests (initialized with the Transaction object) are executed exclusively on this connection. After you call commit or rollback, connection is then released back to the connection pool.

const transaction = new sql.Transaction(/* [pool] */)

If you omit connection argument, global connection is used instead.

Example

const transaction = new sql.Transaction(/* [pool] */)
transaction.begin(err => {
    // ... error checks

    const request = new sql.Request(transaction)
    request.query('insert into mytable (mycolumn) values (12345)', (err, result) => {
        // ... error checks

        transaction.commit(err => {
            // ... error checks

            console.log("Transaction committed.")
        })
    })
})

Transaction can also be created by const transaction = pool.transaction(). Requests can also be created by const request = transaction.request().

Aborted transactions

This example shows how you should correctly handle transaction errors when abortTransactionOnError (XACT_ABORT) is enabled. Added in 2.0.

const transaction = new sql.Transaction(/* [pool] */)
transaction.begin(err => {
    // ... error checks

    let rolledBack = false

    transaction.on('rollback', aborted => {
        // emited with aborted === true

        rolledBack = true
    })

    new sql.Request(transaction)
    .query('insert into mytable (bitcolumn) values (2)', (err, result) => {
        // insert should fail because of invalid value

        if (err) {
            if (!rolledBack) {
                transaction.rollback(err => {
                    // ... error checks
                })
            }
        } else {
            transaction.commit(err => {
                // ... error checks
            })
        }
    })
})

Events

• begin - Dispatched when transaction begin.
• commit - Dispatched on successful commit.
• rollback(aborted) - Dispatched on successful rollback with an argument determining if the transaction was aborted (by user or because of an error).

---

begin ([isolationLevel], [callback])

Begin a transaction.

Arguments

• isolationLevel - Controls the locking and row versioning behavior of TSQL statements issued by a connection. Optional. READ_COMMITTED by default. For possible values see sql.ISOLATION_LEVEL.
• callback(err) - A callback which is called after transaction has began, or an error has occurred. Optional. If omitted, returns Promise.

Example

const transaction = new sql.Transaction()
transaction.begin(err => {
    // ... error checks
})

Errors

• ENOTOPEN (ConnectionError) - Connection not yet open.
• EALREADYBEGUN (TransactionError) - Transaction has already begun.

---

commit ([callback])

Commit a transaction.

Arguments

• callback(err) - A callback which is called after transaction has committed, or an error has occurred. Optional. If omitted, returns Promise.

Example

const transaction = new sql.Transaction()
transaction.begin(err => {
    // ... error checks

    transaction.commit(err => {
        // ... error checks
    })
})

Errors

• ENOTBEGUN (TransactionError) - Transaction has not begun.
• EREQINPROG (TransactionError) - Can't commit transaction. There is a request in progress.

---

rollback ([callback])

Rollback a transaction. If the queue isn't empty, all queued requests will be Cancelled and the transaction will be marked as aborted.

Arguments

• callback(err) - A callback which is called after transaction has rolled back, or an error has occurred. Optional. If omitted, returns Promise.

Example

const transaction = new sql.Transaction()
transaction.begin(err => {
    // ... error checks

    transaction.rollback(err => {
        // ... error checks
    })
})

Errors

• ENOTBEGUN (TransactionError) - Transaction has not begun.
• EREQINPROG (TransactionError) - Can't rollback transaction. There is a request in progress.

Prepared Statement

IMPORTANT: always use PreparedStatement class to create prepared statements - it ensures that all your executions of prepared statement are executed on one connection. Once you call prepare, a single connection is acquired from the connection pool and all subsequent executions are executed exclusively on this connection. After you call unprepare, the connection is then released back to the connection pool.

const ps = new sql.PreparedStatement(/* [pool] */)

If you omit the connection argument, the global connection is used instead.

Example

const ps = new sql.PreparedStatement(/* [pool] */)
ps.input('param', sql.Int)
ps.prepare('select @param as value', err => {
    // ... error checks

    ps.execute({param: 12345}, (err, result) => {
        // ... error checks

        // release the connection after queries are executed
        ps.unprepare(err => {
            // ... error checks

        })
    })
})

IMPORTANT: Remember that each prepared statement means one reserved connection from the pool. Don't forget to unprepare a prepared statement when you've finished your queries!

You can execute multiple queries against the same prepared statement but you must unprepare the statement when you have finished using it otherwise you will cause the connection pool to run out of available connections.

TIP: You can also create prepared statements in transactions (new sql.PreparedStatement(transaction)), but keep in mind you can't execute other requests in the transaction until you call unprepare.

---

input (name, type)

Add an input parameter to the prepared statement.

Arguments

• name - Name of the input parameter without @ char.
• type - SQL data type of input parameter.

Example

ps.input('input_parameter', sql.Int)
ps.input('input_parameter', sql.VarChar(50))

Errors (synchronous)

• EARGS (PreparedStatementError) - Invalid number of arguments.
• EINJECT (PreparedStatementError) - SQL injection warning.

---

output (name, type)

Add an output parameter to the prepared statement.

Arguments

• name - Name of the output parameter without @ char.
• type - SQL data type of output parameter.

Example

ps.output('output_parameter', sql.Int)
ps.output('output_parameter', sql.VarChar(50))

Errors (synchronous)

• EARGS (PreparedStatementError) - Invalid number of arguments.
• EINJECT (PreparedStatementError) - SQL injection warning.

---

prepare (statement, [callback])

Prepare a statement.

Arguments

• statement - T-SQL statement to prepare.
• callback(err) - A callback which is called after preparation has completed, or an error has occurred. Optional. If omitted, returns Promise.

Example

const ps = new sql.PreparedStatement()
ps.prepare('select @param as value', err => {
    // ... error checks
})

Errors

• ENOTOPEN (ConnectionError) - Connection not yet open.
• EALREADYPREPARED (PreparedStatementError) - Statement is already prepared.
• ENOTBEGUN (TransactionError) - Transaction has not begun.

---

execute (values, [callback])

Execute a prepared statement.

Arguments

• values - An object whose names correspond to the names of parameters that were added to the prepared statement before it was prepared.
• callback(err) - A callback which is called after execution has completed, or an error has occurred. Optional. If omitted, returns Promise.

Example

const ps = new sql.PreparedStatement()
ps.input('param', sql.Int)
ps.prepare('select @param as value', err => {
    // ... error checks

    ps.execute({param: 12345}, (err, result) => {
        // ... error checks

        console.log(result.recordset[0].value) // return 12345
        console.log(result.rowsAffected) // Returns number of affected rows in case of INSERT, UPDATE or DELETE statement.
        
        ps.unprepare(err => {
            // ... error checks
        })
    })
})

You can also stream executed request.

const ps = new sql.PreparedStatement()
ps.input('param', sql.Int)
ps.prepare('select @param as value', err => {
    // ... error checks

    ps.stream = true
    const request = ps.execute({param: 12345})

    request.on('recordset', columns => {
        // Emitted once for each recordset in a query
    })

    request.on('row', row => {
        // Emitted for each row in a recordset
    })

    request.on('error', err => {
        // May be emitted multiple times
    })

    request.on('done', result => {
        // Always emitted as the last one
        
        console.log(result.rowsAffected) // Returns number of affected rows in case of INSERT, UPDATE or DELETE statement.
        
        ps.unprepare(err => {
            // ... error checks
        })
    })
})

TIP: To learn more about how number of affected rows works, see section Affected Rows.

Errors

• ENOTPREPARED (PreparedStatementError) - Statement is not prepared.
• ETIMEOUT (RequestError) - Request timeout.
• EREQUEST (RequestError) - Message from SQL Server
• ECANCEL (RequestError) - Cancelled.

---

unprepare ([callback])

Unprepare a prepared statement.

Arguments

• callback(err) - A callback which is called after unpreparation has completed, or an error has occurred. Optional. If omitted, returns Promise.

Example

const ps = new sql.PreparedStatement()
ps.input('param', sql.Int)
ps.prepare('select @param as value', err => {
    // ... error checks

    ps.unprepare(err => {
        // ... error checks

    })
})

Errors

• ENOTPREPARED (PreparedStatementError) - Statement is not prepared.

CLI

Before you can start using CLI, you must install mssql globally with npm install mssql -g. Once you do that you will be able to execute mssql command.

Setup

Create a .mssql.json configuration file (anywhere). Structure of the file is the same as the standard configuration object.

{
    "user": "...",
    "password": "...",
    "server": "localhost",
    "database": "..."
}

Example

echo "select * from mytable" | mssql /path/to/config

Results in:

[[{"username":"patriksimek","password":"tooeasy"}]]

You can also query for multiple recordsets.

echo "select * from mytable; select * from myothertable" | mssql

Results in:

[[{"username":"patriksimek","password":"tooeasy"}],[{"id":15,"name":"Product name"}]]

If you omit config path argument, mssql will try to load it from current working directory.

Geography and Geometry

node-mssql has built-in serializer for Geography and Geometry CLR data types.

select geography::STGeomFromText('LINESTRING(-122.360 47.656, -122.343 47.656 )', 4326)
select geometry::STGeomFromText('LINESTRING (100 100 10.3 12, 20 180, 180 180)', 0)

Results in:

{ srid: 4326,
  version: 1,
  points: [ { x: 47.656, y: -122.36 }, { x: 47.656, y: -122.343 } ],
  figures: [ { attribute: 1, pointOffset: 0 } ],
  shapes: [ { parentOffset: -1, figureOffset: 0, type: 2 } ],
  segments: [] }

{ srid: 0,
  version: 1,
  points:
   [ { x: 100, y: 100, z: 10.3, m: 12 },
     { x: 20, y: 180, z: NaN, m: NaN },
     { x: 180, y: 180, z: NaN, m: NaN } ],
  figures: [ { attribute: 1, pointOffset: 0 } ],
  shapes: [ { parentOffset: -1, figureOffset: 0, type: 2 } ],
  segments: [] }

Table-Valued Parameter (TVP)

Supported on SQL Server 2008 and later. You can pass a data table as a parameter to stored procedure. First, we have to create custom type in our database.

CREATE TYPE TestType AS TABLE ( a VARCHAR(50), b INT );

Next we will need a stored procedure.

CREATE PROCEDURE MyCustomStoredProcedure (@tvp TestType readonly) AS SELECT * FROM @tvp

Now let's go back to our Node.js app.

const tvp = new sql.Table() // You can optionally specify table type name in the first argument.

// Columns must correspond with type we have created in database.
tvp.columns.add('a', sql.VarChar(50))
tvp.columns.add('b', sql.Int)

// Add rows
tvp.rows.add('hello tvp', 777) // Values are in same order as columns.

You can send table as a parameter to stored procedure.

const request = new sql.Request()
request.input('tvp', tvp)
request.execute('MyCustomStoredProcedure', (err, result) => {
    // ... error checks

    console.dir(result.recordsets[0][0]) // {a: 'hello tvp', b: 777}
})

TIP: You can also create Table variable from any recordset with recordset.toTable(). You can optionally specify table type name in the first argument.

Affected Rows

If you're performing INSERT, UPDATE or DELETE in a query, you can read number of affected rows. The rowsAffected variable is an array of numbers. Each number represents number of affected rows by a single statement.

Example using Promises

const request = new sql.Request()
request.query('update myAwesomeTable set awesomness = 100').then(result => {
    console.log(result.rowsAffected)
})

Example using callbacks

const request = new sql.Request()
request.query('update myAwesomeTable set awesomness = 100', (err, result) => {
    console.log(result.rowsAffected)
})

Example using streaming

const request = new sql.Request()
request.stream = true
request.query('update myAwesomeTable set awesomness = 100')
request.on('done', result => {
    console.log(result.rowsAffected)
})

JSON support

SQL Server 2016 introduced built-in JSON serialization. By default, JSON is returned as a plain text in a special column named JSON_F52E2B61-18A1-11d1-B105-00805F49916B.

Example

SELECT
    1 AS 'a.b.c',
    2 AS 'a.b.d',
    3 AS 'a.x',
    4 AS 'a.y'
FOR JSON PATH

Results in:

recordset = [ { 'JSON_F52E2B61-18A1-11d1-B105-00805F49916B': '{"a":{"b":{"c":1,"d":2},"x":3,"y":4}}' } ]

You can enable built-in JSON parser with config.parseJSON = true. Once you enable this, recordset will contain rows of parsed JS objects. Given the same example, result will look like this:

recordset = [ { a: { b: { c: 1, d: 2 }, x: 3, y: 4 } } ]

IMPORTANT: In order for this to work, there must be exactly one column named JSON_F52E2B61-18A1-11d1-B105-00805F49916B in the recordset.

More information about JSON support can be found in official documentation.

Errors

There are 4 types of errors you can handle:

• ConnectionError - Errors related to connections and connection pool.
• TransactionError - Errors related to creating, committing and rolling back transactions.
• RequestError - Errors related to queries and stored procedures execution.
• PreparedStatementError - Errors related to prepared statements.

Those errors are initialized in node-mssql module and its original stack may be cropped. You can always access original error with err.originalError.

SQL Server may generate more than one error for one request so you can access preceding errors with err.precedingErrors.

Error Codes

Each known error has name, code and message properties.

Name	Code	Message
ConnectionError	ELOGIN	Login failed.
ConnectionError	ETIMEOUT	Connection timeout.
ConnectionError	EDRIVER	Unknown driver.
ConnectionError	EALREADYCONNECTED	Database is already connected!
ConnectionError	EALREADYCONNECTING	Already connecting to database!
ConnectionError	ENOTOPEN	Connection not yet open.
ConnectionError	EINSTLOOKUP	Instance lookup failed.
ConnectionError	ESOCKET	Socket error.
ConnectionError	ECONNCLOSED	Connection is closed.
TransactionError	ENOTBEGUN	Transaction has not begun.
TransactionError	EALREADYBEGUN	Transaction has already begun.
TransactionError	EREQINPROG	Can't commit/rollback transaction. There is a request in progress.
TransactionError	EABORT	Transaction has been aborted.
RequestError	EREQUEST	Message from SQL Server. Error object contains additional details.
RequestError	ECANCEL	Cancelled.
RequestError	ETIMEOUT	Request timeout.
RequestError	EARGS	Invalid number of arguments.
RequestError	EINJECT	SQL injection warning.
RequestError	ENOCONN	No connection is specified for that request.
PreparedStatementError	EARGS	Invalid number of arguments.
PreparedStatementError	EINJECT	SQL injection warning.
PreparedStatementError	EALREADYPREPARED	Statement is already prepared.
PreparedStatementError	ENOTPREPARED	Statement is not prepared.

Detailed SQL Errors

SQL errors (RequestError with err.code equal to EREQUEST) contains additional details.

• err.number - The error number.
• err.state - The error state, used as a modifier to the number.
• err.class - The class (severity) of the error. A class of less than 10 indicates an informational message. Detailed explanation can be found here.
• err.lineNumber - The line number in the SQL batch or stored procedure that caused the error. Line numbers begin at 1; therefore, if the line number is not applicable to the message, the value of LineNumber will be 0.
• err.serverName - The server name.
• err.procName - The stored procedure name.

Informational messages

To receive informational messages generated by PRINT or RAISERROR commands use:

const request = new sql.Request()
request.on('info', info => {
    console.dir(info)
})
request.query('print \'Hello world.\';', (err, result) => {
    // ...
})

Structure of informational message:

• info.message - Message.
• info.number - The message number.
• info.state - The message state, used as a modifier to the number.
• info.class - The class (severity) of the message. Equal or lower than 10. Detailed explanation can be found here.
• info.lineNumber - The line number in the SQL batch or stored procedure that generated the message. Line numbers begin at 1; therefore, if the line number is not applicable to the message, the value of LineNumber will be 0.
• info.serverName - The server name.
• info.procName - The stored procedure name.

Metadata

Recordset metadata are accessible through the recordset.columns property.

const request = new sql.Request()
request.query('select convert(decimal(18, 4), 1) as first, \'asdf\' as second', (err, result) => {
    console.dir(result.recordset.columns)

    console.log(result.recordset.columns.first.type === sql.Decimal) // true
    console.log(result.recordset.columns.second.type === sql.VarChar) // true
})

Columns structure for example above:

{
    first: {
        index: 0,
        name: 'first',
        length: 17,
        type: [sql.Decimal],
        scale: 4,
        precision: 18,
        nullable: true,
        caseSensitive: false
        identity: false
        readOnly: true
    },
    second: {
        index: 1,
        name: 'second',
        length: 4,
        type: [sql.VarChar],
        nullable: false,
        caseSensitive: false
        identity: false
        readOnly: true
    }
}

Data Types

You can define data types with length/precision/scale:

request.input("name", sql.VarChar, "abc")               // varchar(3)
request.input("name", sql.VarChar(50), "abc")           // varchar(50)
request.input("name", sql.VarChar(sql.MAX), "abc")      // varchar(MAX)
request.output("name", sql.VarChar)                     // varchar(8000)
request.output("name", sql.VarChar, "abc")              // varchar(3)

request.input("name", sql.Decimal, 155.33)              // decimal(18, 0)
request.input("name", sql.Decimal(10), 155.33)          // decimal(10, 0)
request.input("name", sql.Decimal(10, 2), 155.33)       // decimal(10, 2)

request.input("name", sql.DateTime2, new Date())        // datetime2(7)
request.input("name", sql.DateTime2(5), new Date())     // datetime2(5)

List of supported data types:

sql.Bit
sql.BigInt
sql.Decimal ([precision], [scale])
sql.Float
sql.Int
sql.Money
sql.Numeric ([precision], [scale])
sql.SmallInt
sql.SmallMoney
sql.Real
sql.TinyInt

sql.Char ([length])
sql.NChar ([length])
sql.Text
sql.NText
sql.VarChar ([length])
sql.NVarChar ([length])
sql.Xml

sql.Time ([scale])
sql.Date
sql.DateTime
sql.DateTime2 ([scale])
sql.DateTimeOffset ([scale])
sql.SmallDateTime

sql.UniqueIdentifier

sql.Variant

sql.Binary
sql.VarBinary ([length])
sql.Image

sql.UDT
sql.Geography
sql.Geometry

To setup MAX length for VarChar, NVarChar and VarBinary use sql.MAX length. Types sql.XML and sql.Variant are not supported as input parameters.

SQL injection

This module has built-in SQL injection protection. Always use parameters or tagged template literals to pass sanitized values to your queries.

const request = new sql.Request()
request.input('myval', sql.VarChar, '-- commented')
request.query('select @myval as myval', (err, result) => {
    console.dir(result)
})

Known issues

Tedious

• If you're facing problems with connecting SQL Server 2000, try setting the default TDS version to 7.1 with config.options.tdsVersion = '7_1' (issue)
• If you're executing a statement longer than 4000 chars on SQL Server 2000, always use batch instead of query (issue)

msnodesqlv8

• msnodesqlv8 has problem with errors during transactions - reported.
• msnodesqlv8 doesn't support detailed SQL errors.

5.x to 6.x changes

• Upgraded tarn.js so _poolDestroy can take advantage of being a promise
• ConnectionPool.close() now returns a promise / callbacks will be executed once closing of the pool is complete; you must make sure that connections are properly released back to the pool otherwise the pool may fail to close.
• It is safe to pass read-only config objects to the library; config objects are now cloned
• options.encrypt is now true by default
• TYPES.Null has now been removed
• Upgraded tedious driver to v6 and upgraded support for msnodesqlv8]
• You can now close the global connection by reference and this will clean up the global connection, eg: const conn = sql.connect(); conn.close() will be the same as sql.close()
• Bulk table inserts will attempt to coerce dates from non-Date objects if the column type is expecting a date
• Repeat calls to the global connect function (sql.connect()) will return the current global connection if it exists (rather than throwing an error)
• Attempting to add a parameter to queries / stored procedures will now throw an error; use replaceInput and replaceOutput instead
• Invalid isolation levels passed to Transactions will now throw an error
• ConnectionPool now reports if it is healthy or not (ConnectionPool.healthy) which can be used to determine if the pool is able to create new connections or not
• Pause/Resume support for streamed results has been added to the msnodesqlv8 driver

4.x to 5.x changes

• Moved pool library from node-pool to tarn.js
• ConnectionPool.pool.size deprecated, use ConnectionPool.size instead
• ConnectionPool.pool.available deprecated, use ConnectionPool.available instead
• ConnectionPool.pool.pending deprecated, use ConnectionPool.pending instead
• ConnectionPool.pool.borrowed deprecated, use ConnectionPool.borrowed instead

3.x to 4.x changes

• Library & tests are rewritten to ES6.
• Connection was renamed to ConnectionPool.
• Drivers are no longer loaded dynamically so the library is now compatible with Webpack. To use msnodesqlv8 driver, use const sql = require('mssql/msnodesqlv8') syntax.
• Every callback/resolve now returns result object only. This object contains recordsets (array of recordsets), recordset (first recordset from array of recordsets), rowsAffected (array of numbers representig number of affected rows by each insert/update/delete statement) and output (key/value collection of output parameters' values).
• Affected rows are now returned as an array. A separate number for each SQL statement.
• Directive multiple: true was removed.
• Transaction and PreparedStatement internal queues was removed.
• ConnectionPool no longer emits connect and close events.
• Removed verbose and debug mode.
• Removed support for tds and msnodesql drivers.
• Removed support for Node versions lower than 4.