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

Declaring Program Data

As I mentioned, before you can make a reference to a variable or a constant, you must declare it. (The only exception to this rule is for the index variables of FOR loops .) All declarations must be made in the declaration section of your anonymous block, procedure, function, trigger, object type body, or package body. You can declare many types of data and data structures in PL/SQL, including variables, constants, TYPEs (such as a type of collection or a type of record), and exceptions. This section focuses on the declarations of variables and constants.

Declaring a variable

When you declare a variable, PL/SQL allocates memory for the variable’s value and names the storage location so that the value can be retrieved and changed. The declaration also specifies the datatype of the variable; this datatype is then used to validate values assigned to the variable.

The basic syntax for a declaration is:

    name datatype [NOT NULL] [default_assignment];

where name is the name of the variable or constant to be declared, and datatypeis the datatype or subtype that determines the type of data that can be assigned to the variable. You can include a NOT NULL clause , which means that if your code assigns a NULL to this variable, Oracle will raise an exception. The [default_assignment] clause allows you to initialize the variable with a value; this is optional for all declarations except those of constants.

The following examples illustrate declarations of variables of different ...