The dbcursor command creates a database cursor. The returned
cursor handle is bound to a Tcl command of the form dbN.cX, where
X is an integer starting at 0 (e.g., db0.c0 and db0.c1). It is through
this Tcl command that the script accesses the cursor methods.
The options are as follows:
-txn txnid
If the file is being accessed under transaction protection, the
txnid parameter is a transaction handle returned from envtxn.