db join

db join

The db join command joins the specified cursors and returns a cursor handle that can be used to iterate through the joined {key data} pairs. The returned cursor handle is bound to a Tcl command of the form dbN.cX, where X is an integer starting at 0 (for example, db0.c0 and db0.c1). It is through this Tcl command that the script accesses the cursor methods.

The returned join cursor has limited cursor functionality, and only the dbc get and dbc close commands will succeed.

See Equality Join in the Berkeley DB Programmer's Reference Guide for more information on the underlying requirements for joining.

In a transaction-protected environment, all the cursors listed must have been created within the same transaction.

In the case of error, a Tcl error is thrown.