book

Oracle PL/SQL for DBAs

by Arup Nanda, Steven Feuerstein

October 2005

Intermediate to advanced

454 pages

14h 44m

English

O'Reilly Media, Inc.

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1.2.1.1. Sections of the block1.2.1.2. Anonymous blocks
1.2.3.1. NULLs
1.2.4.1. String literals1.2.4.2. Numeric literals1.2.4.3. Boolean literals
1.2.6.1. Single-line comment syntax1.2.6.2. Multi-line comment syntax
1.3.1.1. Character data1.3.1.2. Numbers1.3.1.3. Dates, timestamps, and intervals1.3.1.4. Booleans1.3.1.5. Binary data1.3.1.6. ROWIDs1.3.1.7. REF CURSOR datatype1.3.1.8. Internet datatypes1.3.1.9. “Any” datatypes
1.3.2.1. Declaring a variable1.3.2.2. Declaring constants1.3.2.3. Anchored declarations
1.4.2.1. Simple CASE statement1.4.2.2. Searched CASE statement
1.6.2.1. RAISE statement1.6.2.2. Using RAISE_APPLICATION_ERROR
1.6.3.1. Built-in error functions1.6.3.2. Unhandled exceptions1.6.3.3. Propagation of an unhandled exception
1.7.2.1. Record-level operations1.7.2.2. Field-level operations
1.8.2.1. Using an associative array1.8.2.2. Using a nested table1.8.2.3. Using a VARRAY
1.9.1.1. Structure of a procedure1.9.1.2. Calling a procedure
1.9.2.1. Structure of a function1.9.2.2. Calling a function
1.9.3.1. Defining parameters1.9.3.2. Actual and formal parameters1.9.3.3. Parameter modes
1.9.4.1. Rules for building packages1.9.4.2. Rules for calling packaged elements1.9.4.3. Package data
1.10.3.1. Error handling with implicit cursors1.10.3.2. Implicit SQL cursor attributes
1.10.5.1. Limiting rows retrieved with BULK COLLECT
1.10.6.1. Declaring REF CURSOR types1.10.6.2. Declaring cursor variables1.10.6.3. Opening cursor variables1.10.6.4. Fetching from cursor variables
1.11.6.1. Syntax of the FORALL Statement1.11.6.2. FORALL Examples
1.13.1.1. Transaction participation1.13.1.2. Creating a DML trigger1.13.1.3. The WHEN clause1.13.1.4. Working with NEW and OLD pseudo -records1.13.1.5. Determining the DML action within a trigger
1.13.2.1. Creating a DDL Trigger
1.13.3.1. Creating a database event trigger
2.4.2.1. Strong vs. weak REF cursors2.4.2.2. REF cursor attributes2.4.2.3. Dynamic data access
3.3.2.1. Random partitioning (PARTITION BY ANY)3.3.2.2. Range partitioning (PARTITION BY RANGE)3.3.2.3. Order streaming (ORDER)3.3.2.4. Hash partitioning (PARTITION BY HASH)3.3.2.5. Cluster streaming (CLUSTER)
4.2.7.1. Using DES3GETKEY4.2.7.2. Using the key in encryption
4.3.3.1. Specifying the encryption type4.3.3.2. Specifying chaining4.3.3.3. Specifying padding4.3.3.4. Combining options in the typ parameter4.3.3.5. Handling and converting RAW data4.3.3.6. Specifying the encryption algorithm4.3.3.7. Putting it together
5.2.2.1. Problems with static policies5.2.2.2. Using a pragma
5.3.2.1. Shared static policy5.3.2.2. Context-sensitive policy5.3.2.3. Shared context-sensitive policy
5.4.3.1. Data dictionary view5.4.3.2. Event-based tracing
6.2.3.1. Turning off bind variable capture
6.2.4.1. Drawbacks with the default FGA approach6.2.4.2. Creating a user-defined audit facility
6.3.2.1. The ADD_POLICY procedure6.3.2.2. The DROP_POLICY procedure6.3.2.3. The DISABLE_POLICY procedure6.3.2.4. The ENABLE_POLICY procedure
6.4.2.1. The DBA_FGA_AUDIT_TRAIL view6.4.2.2. The FLASHBACK_TRANSACTION_QUERY view
6.5.1.1. The case for FGA6.5.1.2. The case for triggers
7.1.1.1. Controlling the precision7.1.1.2. Controlling the range
7.1.2.1. The RANDOM function
8.2.1.1. Running OS executables and anonymous blocks8.2.1.2. DBA_SCHEDULER_JOBS view
8.2.2.1. Enabling and disabling jobs8.2.2.2. Stopping running jobs8.2.2.3. Running a job8.2.2.4. Dropping a job
8.3.1.1. Examples of calendar strings8.3.1.2. Determining future calendar strings
8.7.1.1. DBA_SCHEDULER_JOB_LOG8.7.1.2. DBA_SCHEDULER_JOB_RUN_DETAILS8.7.1.3. Pruning the job log8.7.1.4. Log levels8.7.1.5. Setting the retention period
8.7.2.1. DBA_SCHEDULER_WINDOW_LOG8.7.2.2. DBA_SCHEDULER_WINDOW_DETAILS

Content preview from Oracle PL/SQL for DBAs

PL/SQL Block Structure

In PL/SQL, as in most other procedural languages, the smallest meaningful grouping of code is known as a block. A block is a unit of code that provides execution and scoping boundaries for variable declarations and exception handling. PL/SQL allows you to create anonymous blocks (blocks of code that have no name) and named blocks , which may be procedures, functions, or triggers.

In the sections below, we review the structure of a block and focus on the anonymous block. We’ll explore the different kinds of named blocks later in this chapter.

Sections of the block

A PL/SQL block has up to four different sections, only one of which is mandatory. Figure 1-1 illustrates the block structure.

Figure 1-1. The PL/SQL block structure

Header: Used only for named blocks . The header determines the way the named block or program must be called. Optional.
Declaration section: Identifies variables, cursors, and sub-blocks that are referenced in the execution and exception sections. Optional.
Execution section: Contains statements that the PL/SQL runtime engine will execute at runtime. Mandatory.
Exception section: Handles exceptions to normal processing (warnings and error conditions). Optional.

Anonymous blocks

When someone wishes to remain anonymous, that person goes unnamed. The same is true of the anonymous block in PL/SQL, which is shown in Figure 1-2: it lacks a header section ...