Connection Options

Download PHP driver

This topic lists the options that are permitted in the associative array (when using sqlsrv_connect in the SQLSRV driver) or the keywords that are permitted in the data source name (dsn) (when using PDO::__construct in the PDO_SQLSRV driver).

Table of Connection Options

Key	Value	Description	Default
AccessToken	String	The byte string of the Microsoft Entra access token extracted from an OAuth JSON response. The connection string must not contain a user ID, password, or the Authentication keyword. For more information, see Connect Using Microsoft Entra authentication	Not set.
APP	String	Specifies the application name used in tracing.	Not set.
ApplicationIntent	String	Declares the application workload type when connecting to a server. Possible values are ReadOnly and ReadWrite. For more information about Microsoft Drivers for PHP for SQL Server support for Always On availability groups, see Support for High Availability, Disaster Recovery.	ReadWrite
AttachDBFileName	String	Specifies which database file the server should attach.	Not set.
Authentication	One of the following strings: SqlPassword ActiveDirectoryPassword ActiveDirectoryMsi ActiveDirectoryServicePrincipal	Specifies the authentication mode. For more information, see Connect Using Microsoft Entra authentication	Not set.
CharacterSet (not supported in the PDO_SQLSRV driver)	String	Specifies the character set used to send data to the server. Possible values are SQLSRV_ENC_CHAR and UTF-8. For more information, see How to: Send and Retrieve UTF-8 Data Using Built-In UTF-8 Support.	SQLSRV_ENC_CHAR
ColumnEncryption	One of the following strings: Enabled Disabled A string identifying the attestation protocol and URL for attesting the enclave	Specifies whether the Always Encrypted feature is enabled or not. If an attestation protocol and URL are specified, Always Encrypted with secure enclaves is enabled, provided the other requirements are met as described here.	Disabled
ConnectionPooling	1 or true for connection pooling on. 0 or false for connection pooling off.	Specifies whether the connection is assigned from a connection pool (1 or true) or not (0 or false).1	true (1)
ConnectRetryCount	Integer between 0 and 255 (inclusive)	The maximum number of attempts to reestablish a broken connection before giving up. By default, a single attempt is made to reestablish a connection when broken. A value of 0 means that no reconnection will be attempted.	1
ConnectRetryInterval	Integer between 1 and 60 (inclusive)	The time, in seconds, between attempts to reestablish a connection. The application will attempt to reconnect immediately upon detecting a broken connection, and will then wait ConnectRetryInterval seconds before trying again. This keyword is ignored if ConnectRetryCount is equal to 0.	10
Database	String	Specifies the name of the database in use for the connection being established2.	The default database for the login being used.
DecimalPlaces (not supported in the PDO_SQLSRV driver)	Integer between 0 and 4 (inclusive)	Specifies the decimal places when formatting fetched money values. This option works only when FormatDecimals is true. Any negative integer or value more than 4 will be ignored.	Default precision and scale
Driver	String	Specifies the Microsoft ODBC driver used to communicate with SQL Server. Possible values are: ODBC Driver 18 for SQL Server ODBC Driver 17 for SQL Server ODBC Driver 13 for SQL Server ODBC Driver 11 for SQL Server (Windows only).	When the Driver keyword is not specified, the Microsoft Drivers for PHP for SQL Server attempt to find supported Microsoft ODBC driver(s) in the system, starting with the latest version of ODBC and so on.
Encrypt	1 or true for encryption on. 0 or false for encryption off.	Specifies whether the communication with SQL Server is encrypted (1 or true) or unencrypted (0 or false)3.	false (0)
Failover_Partner	String	Specifies the server and instance of the database's mirror (if enabled and configured) to use when the primary server is unavailable. There are restrictions to using Failover_Partner with MultiSubnetFailover. For more information, see Support for High Availability, Disaster Recovery. This option is not supported on Linux or macOS because database mirroring is not supported by the ODBC driver on Linux or macOS. Instead, use Always On availability groups and set the MultiSubnetFailover and TransparentNetworkIPResolution options.	Not set.
FormatDecimals (not supported in the PDO_SQLSRV driver)	1 or true to format fetched decimal strings. 0 or false for default decimal formatting behavior.	Specifies whether to add leading zeroes to decimal strings when appropriate and enables the DecimalPlaces option for formatting money types. If left false, the default behavior of returning exact precision and omitting leading zeroes for values less than 1 is used. For more information, see Formatting Decimal Strings and Money Values.	false (0)
KeyStoreAuthentication	KeyVaultPassword KeyVaultClientSecret	Authentication method for accessing Azure Key Vault. Controls what kind of credentials are used with KeyStorePrincipalId and KeyStoreSecret. For more information, see Using Azure Key Vault.	Not set.
KeyStorePrincipalId	String	Identifier for the account seeking to access Azure Key Vault. If KeyStoreAuthentication is KeyVaultPassword, this value must be a Microsoft Entra username. If KeyStoreAuthentication is KeyVaultClientSecret, this value must be an application client ID.	Not set.
KeyStoreSecret	String	Credential secret for the account seeking to access Azure Key Vault. If KeyStoreAuthentication is KeyVaultPassword, this value must be a Microsoft Entra password. If KeyStoreAuthentication is KeyVaultClientSecret, this value must be an application client secret.	Not set.
Language	String	Specifies the language of messages returned by the server. The available languages are listed in the sys.syslanguages table. This option does not affect the language used by the drivers themselves, as they are currently available only in English, and it does not affect the language of the underlying ODBC driver, whose language is determined by the localized version installed on the client system. Therefore, changing this setting may result in messages being returned in different languages, depending on whether they come from the PHP driver, the ODBC driver, or SQL Server.	The default is the language set in SQL Server.
LoginTimeout	Integer (SQLSRV driver) String (PDO_SQLSRV driver)	Specifies the number of seconds to wait before failing the connection attempt.	No timeout.
MultipleActiveResultSets	1 or true to use multiple active result sets. 0 or false to disable multiple active result sets.	Disables or explicitly enables support for multiple active result sets (MARS). For more information, see How to: Disable Multiple Active Result Sets (MARS).	true (1)
MultiSubnetFailover	String	Always specify multiSubnetFailover=yes when connecting to the availability group listener of a SQL Server 2012 (11.x) availability group or a SQL Server 2012 (11.x) Failover Cluster Instance. multiSubnetFailover=yes configures Microsoft Drivers for PHP for SQL Server to provide faster detection of and connection to the (currently) active server. Possible values are Yes and No. For more information about Microsoft Drivers for PHP for SQL Server support for Always On availability groups, see Support for High Availability, Disaster Recovery.	No
PWD (not supported in the PDO_SQLSRV driver)	String	Specifies the password associated with the User ID to be used when connecting with SQL Server Authentication4.	Not set.
QuotedId	1 or true to use SQL-92 rules. 0 or false to use legacy rules.	Specifies whether to use SQL-92 rules for quoted identifiers (1 or true) or to use legacy Transact-SQL rules (0 or false).	true (1)
ReturnDatesAsStrings (not supported in the PDO_SQLSRV driver)	1 or true to return date and time types as strings. 0 or false to return date and time types as PHP DateTime types.	Retrieves date and time types (datetime, smalldatetime, date, time, datetime2, and datetimeoffset) as strings or as PHP types. For more information, see How to: Retrieve Date and Time Types as Strings Using the SQLSRV Driver. When using the PDO_SQLSRV driver, dates are returned as strings unless otherwise specified. For more information, see How to: Retrieve Date and Time Types as PHP DateTime Objects Using the PDO_SQLSRV Driver.	false
Scrollable	String	"buffered" indicates that you want a client-side (buffered) cursor, which allows you to cache an entire result set in memory. For more information, see Cursor Types (SQLSRV Driver).	Forward-only cursor
Server (not supported in the SQLSRV driver)	String	The SQL Server instance to connect to. You can also specify a virtual network name, to connect to an Always On availability group. For more information about Microsoft Drivers for PHP for SQL Server support for Always On availability groups, see Support for High Availability, Disaster Recovery.	Server is a required keyword (although it does not have to be the first keyword in the connection string). If a server name is not passed to the keyword, an attempt is made to connect to the local instance. The value passed to Server can be the name of a SQL Server instance, or the IP address of the instance. You can optionally specify a port number (for example, sqlsrv:server=(local),1033). Beginning in version 3.0 of the Microsoft Drivers for PHP for SQL Server you can also specify a LocalDB instance with server=(localdb)\instancename. For more information, see Support for LocalDB.
TraceFile	String	Specifies the path for the file used for trace data.	Not set.
TraceOn	1 or true to enable tracing. 0 or false to disable tracing.	Specifies whether ODBC tracing is enabled (1 or true) or disabled (0 or false) for the connection being established.	false (0)
TransactionIsolation	The SQLSRV driver uses the following values: SQLSRV_TXN_READ_UNCOMMITTED SQLSRV_TXN_READ_COMMITTED SQLSRV_TXN_REPEATABLE_READ SQLSRV_TXN_SNAPSHOT SQLSRV_TXN_SERIALIZABLE The PDO_SQLSRV driver uses the following values: PDO::SQLSRV_TXN_READ_UNCOMMITTED PDO::SQLSRV_TXN_READ_COMMITTED PDO::SQLSRV_TXN_REPEATABLE_READ PDO::SQLSRV_TXN_SNAPSHOT PDO::SQLSRV_TXN_SERIALIZABLE	Specifies the transaction isolation level. For more information about transaction isolation, see SET TRANSACTION ISOLATION LEVEL in the SQL Server documentation.	SQLSRV_TXN_READ_COMMITTED or PDO::SQLSRV_TXN_READ_COMMITTED
TransparentNetworkIPResolution	Enabled or Disabled	Affects the connection sequence when the first resolved IP of the hostname does not respond and there are multiple IPs associated with the hostname. It interacts with MultiSubnetFailover to provide different connection sequences. For more information, see Transparent Network IP Resolution or Using Transparent Network IP Resolution.	Enabled
TrustServerCertificate	1 or true to trust certificate. 0 or false to not trust certificate.	Specifies whether the client should trust (1 or true) or reject (0 or false) a self-signed server certificate.	false (0)
UID (not supported in the PDO_SQLSRV driver)	String	Specifies the User ID to be used when connecting with SQL Server Authentication4.	Not set.
WSID	String	Specifies the name of the computer for tracing.	Not set.

1. The ConnectionPooling attribute cannot be used to enable/disable connection pooling in Linux and macOS. See Connection Pooling (Microsoft Drivers for PHP for SQL Server).

2. All queries executed on the established connection are made to the database that is specified by the Database attribute. However, if the user has the appropriate permissions, data in other databases can be accessed by using a fully qualified name. For example, if the master database is set with the Database connection attribute, it is still possible to execute a Transact-SQL query that accesses the AdventureWorks.HumanResources.Employee table by using the fully qualified name.

3. Enabling Encryption can impact the performance of some applications due to the computational overhead required to encrypt data.

4. The UID and PWD attributes must both be set when connecting with SQL Server Authentication.

Many of the supported keys are ODBC connection string attributes. For information about ODBC connection strings, see Using Connection String Keywords with SQL Native Client.

See Also

Connecting to the Server