Name
SET CONNECTION
Synopsis
The SET CONNECTION
statement allows users to switch
between several open connections on one or more database servers.
Vendor |
Command |
---|---|
SQL Server |
Supported, with limitations |
MySQL |
Not supported |
Oracle |
Not supported |
PostgreSQL |
Not supported |
SQL99 Syntax and Description
SET CONNECTION {DEFAULT | connection_name}
This command does not end a connection. Instead, it switches from the
current connection to the connection named in the command, or to the
current connection using the DEFAULT
clause.
When switching between connections, the old connection becomes
dormant (without committing any changes), while the new connection
becomes active.
The CONNECT
command must be used to create a new
connection; the DISCONNECT
command is used to
terminate one.
Microsoft SQL Server Syntax and Variations
Microsoft SQL Server supports SET CONNECTION
only in Embedded-SQL (ESQL), but not within its ad hoc querying tool,
SQL Query Analyzer. It supports the full SQL99 syntax.
Example
Here is a full ESQL program in SQL Server that shows
CONNECT
, DISCONNECT
, and
SET CONNECTION
:
EXEC SQL CONNECT TO chicago.pubs AS chicago1 USER sa; EXEC SQL CONNECT TO new_york.pubs AS new_york1 USER read-only; // opens connections to the servers named "chicago" // // and "new_york"// EXEC SQL SET CONNECTION chicago1; EXEC SQL SELECT name FROM employee INTO :name; // sets the chicago1 connection as active and performs work // // within that session // EXEC SQL SET CONNECTION new_york1; EXEC SQL SELECT ...
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