go-mssqldb

A pure Go MSSQL driver for Go's database/sql package

For more recent updates, see the Microsoft fork.

Install

Requires Go 1.8 or above.

Install with go get github.com/denisenkom/go-mssqldb .

Connection Parameters and DSN

The recommended connection string uses a URL format: sqlserver://username:password@host/instance?param1=value&param2=value Other supported formats are listed below.

Common parameters

• user id - enter the SQL Server Authentication user id or the Windows Authentication user id in the DOMAIN\User format. On Windows, if user id is empty or missing Single-Sign-On is used. The user domain sensitive to the case which is defined in the connection string.
• password
• database
• connection timeout - in seconds (default is 0 for no timeout), set to 0 for no timeout. Recommended to set to 0 and use context to manage query and connection timeouts.
• dial timeout - in seconds (default is 15), set to 0 for no timeout
• encrypt
  • disable - Data send between client and server is not encrypted.
  • false - Data sent between client and server is not encrypted beyond the login packet. (Default)
  • true - Data sent between client and server is encrypted.
• app name - The application name (default is go-mssqldb)

Connection parameters for ODBC and ADO style connection strings

• server - host or host\instance (default localhost)
• port - used only when there is no instance in server (default 1433)

Less common parameters

• keepAlive - in seconds; 0 to disable (default is 30)
• failoverpartner - host or host\instance (default is no partner).
• failoverport - used only when there is no instance in failoverpartner (default 1433)
• packet size - in bytes; 512 to 32767 (default is 4096)
  • Encrypted connections have a maximum packet size of 16383 bytes
  • Further information on usage: https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/configure-the-network-packet-size-server-configuration-option
• log - logging flags (default 0/no logging, 63 for full logging)
  • 1 log errors
  • 2 log messages
  • 4 log rows affected
  • 8 trace sql statements
  • 16 log statement parameters
  • 32 log transaction begin/end
• TrustServerCertificate
  • false - Server certificate is checked. Default is false if encrypt is specified.
  • true - Server certificate is not checked. Default is true if encrypt is not specified. If trust server certificate is true, driver accepts any certificate presented by the server and any host name in that certificate. In this mode, TLS is susceptible to man-in-the-middle attacks. This should be used only for testing.
• certificate - The file that contains the public key certificate of the CA that signed the SQL Server certificate. The specified certificate overrides the go platform specific CA certificates.
• hostNameInCertificate - Specifies the Common Name (CN) in the server certificate. Default value is the server host.
• ServerSPN - The kerberos SPN (Service Principal Name) for the server. Default is MSSQLSvc/host:port.
• Workstation ID - The workstation name (default is the host name)
• ApplicationIntent - Can be given the value ReadOnly to initiate a read-only connection to an Availability Group listener. The database must be specified when connecting with Application Intent set to ReadOnly.

The connection string can be specified in one of three formats

1. URL: with sqlserver scheme. username and password appears before the host. Any instance appears as the first segment in the path. All other options are query parameters. Examples:

   • sqlserver://username:password@host/instance?param1=value&param2=value
   • sqlserver://username:password@host:port?param1=value&param2=value
   • sqlserver://sa@localhost/SQLExpress?database=master&connection+timeout=30 // `SQLExpress instance.
   • sqlserver://sa:mypass@localhost?database=master&connection+timeout=30 // username=sa, password=mypass.
   • sqlserver://sa:mypass@localhost:1234?database=master&connection+timeout=30 // port 1234 on localhost.
   • sqlserver://sa:my%7Bpass@somehost?connection+timeout=30 // password is "my{pass" A string of this format can be constructed using the URL type in the net/url package.

   
   query := url.Values{}
   query.Add("app name", "MyAppName")
   
   u := &url.URL{
       Scheme:   "sqlserver",
       User:     url.UserPassword(username, password),
       Host:     fmt.Sprintf("%s:%d", hostname, port),
       // Path:  instance, // if connecting to an instance instead of a port
       RawQuery: query.Encode(),
   }
   db, err := sql.Open("sqlserver", u.String())
   

2. ADO: key=value pairs separated by ;. Values may not contain ;, leading and trailing whitespace is ignored. Examples:

   • server=localhost\\SQLExpress;user id=sa;database=master;app name=MyAppName
   • server=localhost;user id=sa;database=master;app name=MyAppName

   ADO strings support synonyms for database, app name, user id, and server

   • server <= addr, address, network address, data source
   • user id <= user, uid
   • database <= initial catalog
   • app name <= application name

3. ODBC: Prefix with odbc, key=value pairs separated by ;. Allow ; by wrapping values in {}. Examples:

   • odbc:server=localhost\\SQLExpress;user id=sa;database=master;app name=MyAppName
   • odbc:server=localhost;user id=sa;database=master;app name=MyAppName
   • odbc:server=localhost;user id=sa;password={foo;bar} // Value marked with {}, password is "foo;bar"
   • odbc:server=localhost;user id=sa;password={foo{bar} // Value marked with {}, password is "foo{bar"
   • odbc:server=localhost;user id=sa;password={foobar } // Value marked with {}, password is "foobar "
   • odbc:server=localhost;user id=sa;password=foo{bar // Literal {, password is "foo{bar"
   • odbc:server=localhost;user id=sa;password=foo}bar // Literal }, password is "foo}bar"
   • odbc:server=localhost;user id=sa;password={foo{bar} // Literal {, password is "foo{bar"
   • odbc:server=localhost;user id=sa;password={foo}}bar} // Escaped } with}}`, password is "foo}bar"

Azure Active Directory authentication

Azure Active Directory authentication uses temporary authentication tokens to authenticate. The mssql package does not provide an implementation to obtain tokens: instead, import the azuread package and use driver name azuresql. This driver uses azidentity to acquire tokens using a variety of credential types.

The credential type is determined by the new fedauth connection string parameter.

• fedauth=ActiveDirectoryServicePrincipal or fedauth=ActiveDirectoryApplication - authenticates using an Azure Active Directory application client ID and client secret or certificate. Implemented using ClientSecretCredential or CertificateCredential
  • clientcertpath=<path to certificate file>;password=<certificate password> or
  • password=<client secret>
  • user id=<application id>[@tenantid] Note the @tenantid component can be omitted if the server's tenant is the same as the application's tenant.
• fedauth=ActiveDirectoryPassword - authenticates using a user name and password.
  • user id=username@domain
  • password=<password>
  • applicationclientid=<application id> - This guid identifies an Azure Active Directory enterprise application that the AAD admin has approved for accessing Azure SQL database resources in the tenant. This driver does not have an associated application id of its own.
• fedauth=ActiveDirectoryDefault - authenticates using a chained set of credentials. The chain is built from EnvironmentCredential -> ManagedIdentityCredential->AzureCLICredential. See DefaultAzureCredential docs for instructions on setting up your host environment to use it. Using this option allows you to have the same connection string in a service deployment as on your interactive development machine.
• fedauth=ActiveDirectoryManagedIdentity or fedauth=ActiveDirectoryMSI - authenticates using a system-assigned or user-assigned Azure Managed Identity.
  • user id=<identity id> - optional id of user-assigned managed identity. If empty, system-assigned managed identity is used.
• fedauth=ActiveDirectoryInteractive - authenticates using credentials acquired from an external web browser. Only suitable for use with human interaction.
  • applicationclientid=<application id> - This guid identifies an Azure Active Directory enterprise application that the AAD admin has approved for accessing Azure SQL database resources in the tenant. This driver does not have an associated application id of its own.

import (
  "database/sql"
  "net/url"

  // Import the Azure AD driver module (also imports the regular driver package)
  "github.com/denisenkom/go-mssqldb/azuread"
)

func ConnectWithMSI() (*sql.DB, error) {
  return sql.Open(azuread.DriverName, "sqlserver://azuresql.database.windows.net?database=yourdb&fedauth=ActiveDirectoryMSI")
}

Executing Stored Procedures

To run a stored procedure, set the query text to the procedure name:

var account = "abc"
_, err := db.ExecContext(ctx, "sp_RunMe",
	sql.Named("ID", 123),
	sql.Named("Account", sql.Out{Dest: &account}),
)

Reading Output Parameters from a Stored Procedure with Resultset

To read output parameters from a stored procedure with resultset, make sure you read all the rows before reading the output parameters:

sqltextcreate := `
CREATE PROCEDURE spwithoutputandrows
	@bitparam BIT OUTPUT
AS BEGIN
	SET @bitparam = 1
	SELECT 'Row 1'
END
`
var bitout int64
rows, err := db.QueryContext(ctx, "spwithoutputandrows", sql.Named("bitparam", sql.Out{Dest: &bitout}))
var strrow string
for rows.Next() {
	err = rows.Scan(&strrow)
}
fmt.Printf("bitparam is %d", bitout)

Caveat for local temporary tables

Due to protocol limitations, temporary tables will only be allocated on the connection as a result of executing a query with zero parameters. The following query will, due to the use of a parameter, execute in its own session, and #mytemp will be de-allocated right away:

conn, err := pool.Conn(ctx)
defer conn.Close()
_, err := conn.ExecContext(ctx, "select @p1 as x into #mytemp", 1)
// at this point #mytemp is already dropped again as the session of the ExecContext is over

To work around this, always explicitly create the local temporary table in a query without any parameters. As a special case, the driver will then be able to execute the query directly on the connection-scoped session. The following example works:

…

Return Status

To get the procedure return status, pass into the parameters a *mssql.ReturnStatus. For example:

var rs mssql.ReturnStatus
_, err := db.ExecContext(ctx, "theproc", &rs)
log.Printf("status=%d", rs)

or

var rs mssql.ReturnStatus
_, err := db.QueryContext(ctx, "theproc", &rs)
for rows.Next() {
	err = rows.Scan(&val)
}
log.Printf("status=%d", rs)

Limitation: ReturnStatus cannot be retrieved using QueryRow.

Parameters

The sqlserver driver uses normal MS SQL Server syntax and expects parameters in the sql query to be in the form of either @Name or @p1 to @pN (ordinal position).

db.QueryContext(ctx, `select * from t where ID = @ID and Name = @p2;`, sql.Named("ID", 6), "Bob")

Parameter Types

To pass specific types to the query parameters, say varchar or date types, you must convert the types to the type before passing in. The following types