Connection descriptor

A DataBlade® API module (C UDR or client LIBMI application) obtains access to the session context through a connection descriptor, MI_CONNECTION. The connection descriptor is an opaque C data structure that points to the threadsafe context-sensitive portion of the session information.

The session context includes the information in the following table.
Table 1. Session-context information in a connection descriptor
Connection information More information
Save sets Save sets
Statement descriptors:
  • For SQL statement, last executed with mi_exec()
  • For prepared statements
 Execute basic SQL statements

Execute prepared SQL statements
Cursors (implicit and explicit) Queries and implicit cursors and Define an explicit cursor
Resources for the current row of the current statement:
  • Row descriptor
  • Row structure
 Retrieving query data
Function descriptors Obtain a function descriptor
Callbacks registered for the connection Register a callback
User data Associate user data with a connection
The integer byte order of the client computer Conversion of opaque-type data with computer-specific data types

You obtain a connection descriptor when you establish a connection in the DataBlade API module. For more information, see Establish a connection.