Oracle7 Server Tuning

SQL Statement Execution

Figure 4 - 1 outlines the stages commonly used to process and execute a SQL statement. In some cases, Oracle might execute these steps in a slightly different order. For example, the DEFINE stage could occur just before the FETCH stage, depending on how you wrote your code.

The following sections describe each phase of SQL statement processing for each type of SQL statement. As you read this information, remember that for many Oracle tools, several of the phases are performed automatically. Most users need not be concerned with or aware of this level of detail. However, you might find this information useful when writing Oracle applications.

Figure 4 - 1. The Stages in Processing a SQL Statement