Oracle7 Server Application Developer's Guide

SQL Statement Execution

Figure 3 - 1 outlines the stages commonly used to process and execute a SQL statement. In some cases, these steps might be executed in a slightly different order. For example, the DEFINE stage could occur just before the FETCH stage, depending on how your code is written.

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. Refer to the Oracle7 Server Tuning manual for a description of each phase of SQL statement processing for each type of SQL statement.

FIPS Flagging

The Federal Information Processing Standard for SQL (FIPS 127-2) requires a way to identify SQL statements that use vendor-supplied extensions. Oracle provides a FIPS flagger to help you write portable applications.

When FIPS flagging is active, your SQL statements are checked to see whether they include extensions that go beyond the ANSI/ISO SQL92 standard. If any non-standard constructs are found, the Oracle Server flags them as errors and displays the violating syntax.

The FIPS flagging feature supports flagging through interactive SQL statements submitted using Server Manager or SQL*Plus. The Oracle Precompilers and SQL*Module also support FIPS flagging of embedded and module language SQL.

When flagging is on and non-standard SQL is encountered, the message returned is

ORA-00097: Use of Oracle SQL feature not in SQL92 level Level

where level can be either ENTRY, INTERMEDIATE, or FULL.

Figure 3 - 1. The Stages in Processing a SQL Statement