The mssql npm package is a Microsoft SQL Server client for Node.js. It allows you to connect to SQL Server databases, execute queries, and manage transactions. It supports both Promises and async/await syntax, making it versatile for different coding styles.
Connecting to a SQL Server
This code demonstrates how to connect to a SQL Server database using the mssql package. You need to provide your database credentials and server information in the config object.
const sql = require('mssql');
const config = {
user: 'your_username',
password: 'your_password',
server: 'your_server',
database: 'your_database'
};
async function connectToDatabase() {
try {
let pool = await sql.connect(config);
console.log('Connected to the database');
} catch (err) {
console.error('Database connection failed: ', err);
}
}
connectToDatabase();Executing a Query
This code demonstrates how to execute a SQL query using the mssql package. It connects to the database and runs a SELECT query on a specified table.
const sql = require('mssql');
const config = {
user: 'your_username',
password: 'your_password',
server: 'your_server',
database: 'your_database'
};
async function executeQuery() {
try {
let pool = await sql.connect(config);
let result = await pool.request().query('SELECT * FROM your_table');
console.log(result);
} catch (err) {
console.error('Query execution failed: ', err);
}
}
executeQuery();Using Prepared Statements
This code demonstrates how to use prepared statements with the mssql package. Prepared statements are useful for executing queries with parameters, which can help prevent SQL injection attacks.
const sql = require('mssql');
const config = {
user: 'your_username',
password: 'your_password',
server: 'your_server',
database: 'your_database'
};
async function executePreparedStatement() {
try {
let pool = await sql.connect(config);
let ps = new sql.PreparedStatement(pool);
ps.input('input_parameter', sql.Int);
await ps.prepare('SELECT * FROM your_table WHERE id = @input_parameter');
let result = await ps.execute({ input_parameter: 1 });
console.log(result);
await ps.unprepare();
} catch (err) {
console.error('Prepared statement execution failed: ', err);
}
}
executePreparedStatement();Managing Transactions
This code demonstrates how to manage transactions using the mssql package. Transactions allow you to execute a series of queries as a single unit of work, which can be committed or rolled back based on success or failure.
const sql = require('mssql');
const config = {
user: 'your_username',
password: 'your_password',
server: 'your_server',
database: 'your_database'
};
async function manageTransaction() {
try {
let pool = await sql.connect(config);
let transaction = new sql.Transaction(pool);
await transaction.begin();
let request = new sql.Request(transaction);
await request.query('INSERT INTO your_table (column1) VALUES (value1)');
await transaction.commit();
console.log('Transaction committed');
} catch (err) {
console.error('Transaction failed: ', err);
if (transaction) await transaction.rollback();
}
}
manageTransaction();The mysql package is a client for MySQL databases. It provides similar functionalities to mssql, such as connecting to a database, executing queries, and managing transactions. However, it is specifically designed for MySQL databases.
The pg package is a PostgreSQL client for Node.js. Like mssql, it allows you to connect to a database, execute queries, and manage transactions. It is tailored for PostgreSQL databases and offers features specific to PostgreSQL.
The sqlite3 package is a client for SQLite databases. It provides functionalities for connecting to SQLite databases, executing queries, and managing transactions. Unlike mssql, it is designed for lightweight, file-based databases.
Microsoft SQL Server client for Node.js
Supported TDS drivers:
npm install mssql
const sql = require('mssql')
async () => {
try {
// make sure that any items are correctly URL encoded in the connection string
await sql.connect('Server=localhost,1433;Database=database;User Id=username;Password=password;Encrypt=true')
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.
Assuming you have set the appropriate environment variables, you can construct a config object as follows:
const sql = require('mssql')
const sqlConfig = {
user: process.env.DB_USER,
password: process.env.DB_PWD,
database: process.env.DB_NAME,
server: 'localhost',
pool: {
max: 10,
min: 0,
idleTimeoutMillis: 30000
},
options: {
encrypt: true, // for azure
trustServerCertificate: false // change to true for local dev / self-signed certs
}
}
async () => {
try {
// make sure that any items are correctly URL encoded in the connection string
await sql.connect(sqlConfig)
const result = await sql.query`select * from mytable where id = ${value}`
console.dir(result)
} catch (err) {
// ... error checks
}
}
const config = {
user: '...',
password: '...',
server: 'localhost', // You can use 'localhost\\instance' to connect to named instance
database: '...',
}
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
})
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
});
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').
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.
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
})
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('rowsaffected', rowCount => {
// Emitted for each `INSERT`, `UPDATE` or `DELETE` statement
// Requires NOCOUNT to be OFF (default)
})
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();
}
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.
To assist with pool management in your application there is the sql.connect() function that is used to connect to the global connection pool. You can make repeated calls to this function, and if the global pool is already connected, it will resolve to the connected pool. The following example obtains the global connection pool by running sql.connect(), and then runs the query against the pool.
NB: It's important to note that there can only be one global connection pool connected at a time. Providing a different connection config to the connect() function will not create a new connection if it is already connected.
const sql = require('mssql')
const config = { ... }
// 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(config).then((pool) => {
return pool.query(query)
})
}
Awaiting or .then-ing 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 connect() call.
Also notice that we do not close the global pool by calling sql.close() after the query is executed, because other queries may need to be run against this pool and closing it will add additional overhead to running subsequent queries. You should only ever close the global pool if you're certain the application is finished. Or for example, if you are running some kind of CLI tool or a CRON job you can close the pool at the end of the script.
The ability to call connect() and close() repeatedly on the global pool is intended to make pool management easier, however it is better to maintain your own reference to the pool, where connect() is called once, and the resulting global pool's connection promise is re-used throughout the entire application.
For example, in Express applications, the following approach uses a single global pool instance added to the app.locals so the application has access to it when needed. The server start is then chained inside the connect() promise.
const express = require('express')
const sql = require('mssql')
const config = {/*...*/}
//instantiate a connection pool
const appPool = new sql.ConnectionPool(config)
//require route handlers and use the same connection pool everywhere
const route1 = require('./routes/route1')
const app = express()
app.get('/path', route1)
//connect the pool and start the web server when done
appPool.connect().then(function(pool) {
app.locals.db = pool;
const server = app.listen(3000, function () {
const host = server.address().address
const port = server.address().port
console.log('Example app listening at http://%s:%s', host, port)
})
}).catch(function(err) {
console.error('Error creating connection pool', err)
});
Then the route uses the connection pool in the app.locals object:
// ./routes/route1.js
const sql = require('mssql');
module.exports = function(req, res) {
req.app.locals.db.query('SELECT TOP 10 * FROM table_name', function(err, recordset) {
if (err) {
console.error(err)
res.status(500).send('SERVER ERROR')
return
}
res.status(200).json({ message: 'success' })
})
}
For some use-cases you may want to implement your own connection pool management, rather than using the global connection pool. Reasons for doing this include:
The following code is an example of a custom connection pool implementation.
// pool-manager.js
const mssql = require('mssql')
const pools = new Map();
module.exports = {
/**
* Get or create a pool. If a pool doesn't exist the config must be provided.
* If the pool does exist the config is ignored (even if it was different to the one provided
* when creating the pool)
*
* @param {string} name
* @param {{}} [config]
* @return {Promise.<mssql.ConnectionPool>}
*/
get: (name, config) => {
if (!pools.has(name)) {
if (!config) {
throw new Error('Pool does not exist');
}
const pool = new mssql.ConnectionPool(config);
// automatically remove the pool from the cache if `pool.close()` is called
const close = pool.close.bind(pool);
pool.close = (...args) => {
pools.delete(name);
return close(...args);
}
pools.set(name, pool.connect());
}
return pools.get(name);
},
/**
* Closes all the pools and removes them from the store
*
* @return {Promise<mssql.ConnectionPool[]>}
*/
closeAll: () => Promise.all(Array.from(pools.values()).map((connect) => {
return connect.then((pool) => pool.close());
})),
};
This file can then be used in your application to create, fetch, and close pools.
const { get } = require('./pool-manager')
async function example() {
const pool = await get('default')
return pool.request().query('SELECT 1')
}
Similar to the global connection pool, you should aim to only close a pool when you know it will never be needed by the application again. Typically this will only be when your application is shutting down.
In some instances it is desirable to manipulate the record data as it is returned from the database, this may be to cast it as a particular object (eg: moment object instead of Date) or similar.
In v8.0.0+ it is possible to register per-datatype handlers:
const sql = require('mssql')
// in this example all integer values will return 1 more than their actual value in the database
sql.valueHandler.set(sql.TYPES.Int, (value) => value + 1)
sql.query('SELECT * FROM [example]').then((result) => {
// all `int` columns will return a manipulated value as per the callback above
})
The following is an example configuration object:
const config = {
user: '...',
password: '...',
server: 'localhost',
database: '...',
pool: {
max: 10,
min: 0,
idleTimeoutMillis: 30000
}
}
1433). Don't set when connecting to named instance.15000).15000). NOTE: msnodesqlv8 driver doesn't support timeouts < 1 second. When passed via connection string, the key must be request timeoutfalse). 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.false). For more information please see section JSON support.10).0).30000).columns array. (default: false) See Handling Duplicate Column NamesComplete list of pool options can be found here.
In addition to configuration object there is an option to pass config as a connection string. Connection strings are supported.
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
Default driver, actively maintained and production ready. Platform independent, runs everywhere Node.js runs. Officially supported by Microsoft.
Extra options:
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')})
}})
true).true).7_4, available: 7_1, 7_2, 7_3_A, 7_3_B, 7_4).XACT_ABORT during the initial SQL phase of a connection.Authentication:
On top of the extra options, an authentication property can be added to the pool config option
user, password, domain settings.default, ntlm, azure-active-directory-password, azure-active-directory-access-token, azure-active-directory-msi-vm, or azure-active-directory-msi-app-servicetedious driver, depends on authentication.type. For more details, check Tedious Authentication InterfacesMore information about Tedious specific options: http://tediousjs.github.io/tedious/api-connection.html
Requires Node.js v10+ or newer. Windows 32-64 bits or Linux/macOS 64 bits only. This driver is not part of the default package and must be installed separately by npm install msnodesqlv8@^2. To use this driver, use this require syntax: const sql = require('mssql/msnodesqlv8').
Note: If you use import into your lib to prepare your request (const { VarChar } = require('mssql')) you also need to upgrade all your types import into your code (const { VarChar } = require('mssql/msnodesqlv8')) or a connection.on is not a function error will be thrown.
Extra options:
conn is the connection configuration, that can be modified to pass extra parameters to the driver's open() method.false).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}};
Please note that the connection string with this driver is not the same than tedious and use yes/no instead of true/false. You can see more on the ODBC documentation.
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 */ })
Create a new connection pool. The initial probe connection is created to find out whether the configuration is valid.
Arguments
Example
const pool = new sql.ConnectionPool({
user: '...',
password: '...',
server: 'localhost',
database: '...'
})
pool.connect(err => {
// ...
})
Errors
ConnectionError) - Login failed.ConnectionError) - Connection timeout.ConnectionError) - Database is already connected!ConnectionError) - Already connecting to database!ConnectionError) - Instance lookup failed.ConnectionError) - Socket error.Close all active connections in the pool.
Example
pool.close()
const request = new sql.Request(/* [pool or transaction] */)
If you omit pool/transaction argument, global pool is used instead.
Call a stored procedure.
Arguments
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
RequestError) - Message from SQL ServerRequestError) - Cancelled.RequestError) - Request timeout.RequestError) - No connection is specified for that request.ConnectionError) - Connection not yet open.ConnectionError) - Connection is closed.TransactionError) - Transaction has not begun.TransactionError) - Transaction was aborted (by user or because of an error).Add an input parameter to the request.
Arguments
undefined and 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.NVarCharNumber -> sql.IntBoolean -> sql.BitDate -> sql.DateTimeBuffer -> sql.VarBinarysql.Table -> sql.TVPDefault 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)
RequestError) - Invalid number of arguments.RequestError) - SQL injection warning.NB: Do not use parameters @p{n} as these are used by the internal drivers and cause a conflict.
Add an output parameter to the request.
Arguments
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)
RequestError) - Invalid number of arguments.RequestError) - SQL injection warning.Convert request to a Node.js ReadableStream
Example
const { pipeline } = require('stream')
const request = new sql.Request()
const readableStream = request.toReadableStream()
pipeline(readableStream, transformStream, writableStream)
request.query('select * from mytable')
OR if you wanted to increase the highWaterMark of the read stream to buffer more rows in memory
const { pipeline } = require('stream')
const request = new sql.Request()
const readableStream = request.toReadableStream({ highWaterMark: 100 })
pipeline(readableStream, transformStream, writableStream)
request.query('select * from mytable')
Sets request to stream mode and pulls all rows from all recordsets to a given stream.
Arguments
Example
const request = new sql.Request()
request.pipe(stream)
request.query('select * from mytable')
stream.on('error', err => {
// ...
})
stream.on('finish', () => {
// ...
})
Execute the SQL command. To execute commands like create procedure or if you plan to work with local temporary tables, use batch instead.
Arguments
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
RequestError) - Request timeout.RequestError) - Message from SQL ServerRequestError) - Cancelled.RequestError) - No connection is specified for that request.ConnectionError) - Connection not yet open.ConnectionError) - Connection is closed.TransactionError) - Transaction has not begun.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.
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
Example
const request = new sql.Request()
request.batch('create procedure #temporary as select * from table', (err, result) => {
// ... error checks
})
Errors
RequestError) - Request timeout.RequestError) - Message from SQL ServerRequestError) - Cancelled.RequestError) - No connection is specified for that request.ConnectionError) - Connection not yet open.ConnectionError) - Connection is closed.TransactionError) - Transaction has not begun.TransactionError) - Transaction was aborted (by user or because of an error).You can enable multiple recordsets in queries with the request.multiple = true command.
Perform a bulk insert.
Arguments
sql.Table instance.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
RequestError) - Table name must be specified for bulk insert.RequestError) - Request timeout.RequestError) - Message from SQL ServerRequestError) - Cancelled.RequestError) - No connection is specified for that request.ConnectionError) - Connection not yet open.ConnectionError) - Connection is closed.TransactionError) - Transaction has not begun.TransactionError) - Transaction was aborted (by user or because of an error).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()
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
})
}
})
})
Begin a transaction.
Arguments
READ_COMMITTED by default. For possible values see sql.ISOLATION_LEVEL.Example
const transaction = new sql.Transaction()
transaction.begin(err => {
// ... error checks
})
Errors
ConnectionError) - Connection not yet open.TransactionError) - Transaction has already begun.Commit a transaction.
Arguments
Example
const transaction = new sql.Transaction()
transaction.begin(err => {
// ... error checks
transaction.commit(err => {
// ... error checks
})
})
Errors
TransactionError) - Transaction has not begun.TransactionError) - Can't commit transaction. There is a request in progress.Rollback a transaction. If the queue isn't empty, all queued requests will be Cancelled and the transaction will be marked as aborted.
Arguments
Example
const transaction = new sql.Transaction()
transaction.begin(err => {
// ... error checks
transaction.rollback(err => {
// ... error checks
})
})
Errors
TransactionError) - Transaction has not begun.TransactionError) - Can't rollback transaction. There is a request in progress.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.
Add an input parameter to the prepared statement.
Arguments
Example
ps.input('input_parameter', sql.Int)
ps.input('input_parameter', sql.VarChar(50))
Errors (synchronous)
PreparedStatementError) - Invalid number of arguments.PreparedStatementError) - SQL injection warning.Add an output parameter to the prepared statement.
Arguments
Example
ps.output('output_parameter', sql.Int)
ps.output('output_parameter', sql.VarChar(50))
Errors (synchronous)
PreparedStatementError) - Invalid number of arguments.PreparedStatementError) - SQL injection warning.Prepare a statement.
Arguments
Example
const ps = new sql.PreparedStatement()
ps.prepare('select @param as value', err => {
// ... error checks
})
Errors
ConnectionError) - Connection not yet open.PreparedStatementError) - Statement is already prepared.TransactionError) - Transaction has not begun.Execute a prepared statement.
Arguments
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
PreparedStatementError) - Statement is not prepared.RequestError) - Request timeout.RequestError) - Message from SQL ServerRequestError) - Cancelled.Unprepare a prepared statement.
Arguments
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
PreparedStatementError) - Statement is not prepared.If you want to add the MSSQL CLI tool to your path, you must install it globally with npm install -g mssql.
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.
Overriding config settings
You can override some config settings via CLI options (--user, --password, --server, --database, --port).
echo "select * from mytable" | mssql /path/to/config --database anotherdatabase
Results in:
[[{"username":"onotheruser","password":"quiteeasy"}]]
node-mssql has built-in deserializer for Geography and Geometry CLR data types.
Geography types can be constructed several different ways. Refer carefully to documentation to verify the coordinate ordering; the ST methods tend to order parameters as longitude (x) then latitude (y), while custom CLR methods tend to prefer to order them as latitude (y) then longitude (x).
The query:
select geography::STGeomFromText(N'POLYGON((1 1, 3 1, 3 1, 1 1))',4326)
results in:
{
srid: 4326,
version: 2,
points: [
Point { lat: 1, lng: 1, z: null, m: null },
Point { lat: 1, lng: 3, z: null, m: null },
Point { lat: 1, lng: 3, z: null, m: null },
Point { lat: 1, lng: 1, z: null, m: null }
],
figures: [ { attribute: 1, pointOffset: 0 } ],
shapes: [ { parentOffset: -1, figureOffset: 0, type: 3 } ],
segments: []
}
NOTE: You will also see x and y coordinates in parsed Geography points,
they are not recommended for use. They have thus been omitted from this example.
For compatibility, they remain flipped (x, the horizontal offset, is instead used for latitude, the vertical), and thus risk misleading you.
Prefer instead to use the lat and lng properties.
Geometry types can also be constructed in several ways. Unlike Geographies, they are consistent in always placing x before y. node-mssql decodes the result of this query:
select geometry::STGeomFromText(N'POLYGON((1 1, 3 1, 3 7, 1 1))',4326)
into the JavaScript object:
{
srid: 4326,
version: 1,
points: [
Point { x: 1, y: 1, z: null, m: null },
Point { x: 1, y: 3, z: null, m: null },
Point { x: 7, y: 3, z: null, m: null },
Point { x: 1, y: 1, z: null, m: null }
],
figures: [ { attribute: 2, pointOffset: 0 } ],
shapes: [ { parentOffset: -1, figureOffset: 0, type: 3 } ],
segments: []
}
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.
You can clear the table rows for easier batching by using table.rows.clear()
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.
tvp.rows.clear()
An object returned from a sucessful basic query would look like the following.
{
recordsets: [
[
{
COL1: "some content",
COL2: "some more content"
}
]
],
recordset: [
{
COL1: "some content",
COL2: "some more content"
}
],
output: {},
rowsAffected: [1]
}
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
In addition to the rowsAffected attribute on the done event, each statement will emit the number of affected rows as it is completed.
const request = new sql.Request()
request.stream = true
request.query('update myAwesomeTable set awesomness = 100')
request.on('rowsaffected', rowCount => {
console.log(rowCount)
})
request.on('done', result => {
console.log(result.rowsAffected)
})
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.
If your queries contain output columns with identical names, the default behaviour of mssql will only return column metadata for the last column with that name. You will also not always be able to re-assemble the order of output columns requested.
Default behaviour:
const request = new sql.Request()
request
.query("select 'asdf' as name, 'qwerty' as other_name, 'jkl' as name")
.then(result => {
console.log(result)
});
Results in:
{
recordsets: [
[ { name: [ 'asdf', 'jkl' ], other_name: 'qwerty' } ]
],
recordset: [ { name: [ 'asdf', 'jkl' ], other_name: 'qwerty' } ],
output: {},
rowsAffected: [ 1 ]
}
You can use the arrayRowMode configuration parameter to return the row values as arrays and add a separate array of column values. arrayRowMode can be set globally during the initial connection, or per-request.
const request = new sql.Request()
request.arrayRowMode = true
request
.query("select 'asdf' as name, 'qwerty' as other_name, 'jkl' as name")
.then(result => {
console.log(result)
});
Results in:
{
recordsets: [ [ [ 'asdf', 'qwerty', 'jkl' ] ] ],
recordset: [ [ 'asdf', 'qwerty', 'jkl' ] ],
output: {},
rowsAffected: [ 1 ],
columns: [
[
{
index: 0,
name: 'name',
length: 4,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
},
{
index: 1,
name: 'other_name',
length: 6,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
},
{
index: 2,
name: 'name',
length: 3,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
}
]
]
}
Streaming Duplicate Column Names
When using arrayRowMode with stream enabled, the output from the recordset event (as described in Streaming) is returned as an array of column metadata, instead of as a keyed object. The order of the column metadata provided by the recordset event will match the order of row values when arrayRowMode is enabled.
Default behaviour (without arrayRowMode):
const request = new sql.Request()
request.stream = true
request.query("select 'asdf' as name, 'qwerty' as other_name, 'jkl' as name")
request.on('recordset', recordset => console.log(recordset))
Results in:
{
name: {
index: 2,
name: 'name',
length: 3,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
},
other_name: {
index: 1,
name: 'other_name',
length: 6,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
}
}
With arrayRowMode:
const request = new sql.Request()
request.stream = true
request.arrayRowMode = true
request.query("select 'asdf' as name, 'qwerty' as other_name, 'jkl' as name")
request.on('recordset', recordset => console.log(recordset))
Results in:
[
{
index: 0,
name: 'name',
length: 4,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
},
{
index: 1,
name: 'other_name',
length: 6,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
},
{
index: 2,
name: 'name',
length: 3,
type: [sql.VarChar],
scale: undefined,
precision: undefined,
nullable: false,
caseSensitive: false,
identity: false,
readOnly: true
}
]
There are 4 types of errors you can handle:
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.
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. |
SQL errors (RequestError with err.code equal to EREQUEST) contains additional details.
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:
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
}
}
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.
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)
})
config.options.tdsVersion = '7_1' (issue)parseConnectionString on ConnectionPooltrustServerCertificate defaults to false if not suppliedtarn.js so _poolDestroy can take advantage of being a promiseConnectionPool.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.options.encrypt is now true by defaultTYPES.Null has now been removedconst conn = sql.connect(); conn.close() will be the same as sql.close()sql.connect()) will return the current global connection if it exists (rather than throwing an error)replaceInput and replaceOutput insteadTransactions will now throw an errorConnectionPool 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 notnode-pool to tarn.jsConnectionPool.pool.size deprecated, use ConnectionPool.size insteadConnectionPool.pool.available deprecated, use ConnectionPool.available insteadConnectionPool.pool.pending deprecated, use ConnectionPool.pending insteadConnectionPool.pool.borrowed deprecated, use ConnectionPool.borrowed insteadConnection was renamed to ConnectionPool.msnodesqlv8 driver, use const sql = require('mssql/msnodesqlv8') syntax.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).multiple: true was removed.Transaction and PreparedStatement internal queues was removed.connect and close events.tds and msnodesql drivers.FAQs
Microsoft SQL Server client for Node.js.
The npm package mssql receives a total of 637,789 weekly downloads. As such, mssql popularity was classified as popular.
We found that mssql demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 4 open source maintainers collaborating on the project.
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