A pure Go MSSQL driver for Go's database/sql package
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¶m2=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
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 encypt 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
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://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 portRawQuery: query.Encode(),
}
db, err:=sql.Open("sqlserver", u.String())
ADO: key=value pairs separated by ;. Values may not contain ;, leading and trailing whitespace is ignored.
Examples:
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"
)
funcConnectWithMSI() (*sql.DB, error) {
returnsql.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:
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 OUTPUTAS BEGIN SET @bitparam = 1 SELECT 'Row 1'END`varbitoutint64rows, err:=db.QueryContext(ctx, "spwithoutputandrows", sql.Named("bitparam", sql.Out{Dest: &bitout}))
varstrrowstringforrows.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)
deferconn.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:
conn, err:=pool.Conn(ctx)
// Set us up so that temp table is always cleaned up, since conn.Close()// merely returns conn to pool, rather than actually closing the connection.deferfunc() {
_, _=conn.ExecContext(ctx, "drop table #mytemp") // always clean upconn.Close() // merely returns conn to pool
}()
// Since we not pass any parameters below, the query will execute on the scope of// the connection and succeed in creating the table._, err:=conn.ExecContext(ctx, "create table #mytemp ( x int )")
// #mytemp is now available even if you pass parameters_, err:=conn.ExecContext(ctx, "insert into #mytemp (x) values (@p1)", 1)
Return Status
To get the procedure return status, pass into the parameters a
*mssql.ReturnStatus. For example:
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
are supported:
string -> nvarchar
mssql.VarChar -> varchar
time.Time -> datetimeoffset or datetime (TDS version dependent)
mssql.TVP -> Table Value Parameter (TDS version dependent)
Important Notes
LastInsertId should
not be used with this driver (or SQL Server) due to how the TDS protocol
works. Please use the OUTPUT Clause
or add a select ID = convert(bigint, SCOPE_IDENTITY()); to the end of your
query (ref SCOPE_IDENTITY).
This will ensure you are getting the correct ID and will prevent a network round trip.
Connector.SessionInitSQL
may be set to set any driver specific session settings after the session
has been reset. If empty the session will still be reset but use the database
defaults in Go1.10+.
Features
Can be used with SQL Server 2005 or newer
Can be used with Microsoft Azure SQL Database
Can be used on all go supported platforms (e.g. Linux, Mac OS X and Windows)
Supports new date/time types: date, time, datetime2, datetimeoffset
Supports string parameters longer than 8000 characters
Supports encryption using SSL/TLS
Supports SQL Server and Windows Authentication
Supports Single-Sign-On on Windows
Supports connections to AlwaysOn Availability Group listeners, including re-direction to read-only replicas.
Supports query notifications
Tests
go test is used for testing. A running instance of MSSQL server is required.
Environment variables are used to pass login information.
Example:
env SQLSERVER_DSN=sqlserver://user:pass@hostname/instance?database=test1 go test
AZURESERVER_DSN environment variable provides the connection string for Azure Active Directory-based authentication. If it's not set the AAD test will be skipped.
Deprecated
These features still exist in the driver, but they are are deprecated.
Query Parameter Token Replace (driver "mssql")
If you use the driver name "mssql" (rather then "sqlserver") the SQL text
will be loosly parsed and an attempt to extract identifiers using one of
?
?nnn
:nnn
$nnn
will be used. This is not recommended with SQL Server.
There is at least one existing won't fix issue with the query parsing.
Use the native "@Name" parameters instead with the "sqlserver" driver name.
Known Issues
SQL Server 2008 and 2008 R2 engine cannot handle login records when SSL encryption is not disabled.
To fix SQL Server 2008 R2 issue, install SQL Server 2008 R2 Service Pack 2.
To fix SQL Server 2008 issue, install Microsoft SQL Server 2008 Service Pack 3 and Cumulative update package 3 for SQL Server 2008 SP3.
More information: http://support.microsoft.com/kb/2653857
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