Commands

In the client/server model, a server accepts commands from multiple clients and responds by returning data and other information to the clients. Open Client applications use Client-Library routines to communicate commands to servers.

Table 2-19 summarizes the Client-Library command types:

**Table 2-19: Command types**
Command type	Initiated by	Summary
Language	ct_command	Defines the text of a query that the server will parse, interpret, and execute.
RPC, Package	ct_command	Specifies the name of a server procedure (Adaptive Server stored procedure or Open Server registered procedure) to be executed by the server. The procedure must already exist on the server. Package commands are only supported by mainframe Open Server servers. They are otherwise identical to RPC commands.
Cursor	ct_cursor	Initiates one of several commands to manage a Client-Library cursor.
Dynamic SQL	ct_dynamic	Initiates a command to execute a literal SQL statement (with restrictions on statement content) or to manage a prepared dynamic SQL statement.
Message	ct_command	Initiates a message command and specifies the message-command ID number.
Send-Data	ct_command	Initiates a command to upload a large text/image column value to the server.