4 DBMS_PREPROCESSOR

Using DBMS_PREPROCESSOR

• Overview

• Operating notes

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Overview

There are three styles of subprograms:

1. Subprograms that take a schema name, a unit type name, and the unit name.

2. Subprograms that take a VARCHAR2 string which contains the source text of an arbitrary PL/SQL compilation unit.

3. Subprograms that take a VARCHAR2 associative array (index-by table) which contains the segmented source text of an arbitrary PL/SQL compilation unit.

Subprograms of the first style are used to print or retrieve the post-processed source text of a stored PL/SQL unit. The user must have the privileges necessary to view the original source text of this unit. The user must also specify the schema in which the unit is defined, the type of the unit, and the name of the unit. If the schema is null, then the current user schema is used. If the status of the stored unit is VALID and the user has the required privilege, then the post-processed source text is guaranteed to be the same as that of the unit the last time it was compiled. Subprograms of the second or third style are used to generate post-processed source text in the current user schema. The source text is passed in as a single VARCHAR2 string in the second style, or as a VARCHAR2 associative array in the third style. The source text can represent an arbitrary PL/SQL compilation unit. A typical usage is to pass the source text of an anonymous block and generate its post-processed source text in the current user schema. The third style can be useful when the source text exceeds the VARCHAR2 length limit.

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Operating notes

• For subprograms of the first style, the status of the stored PL/SQL unit is not required to be VALID. Likewise, the source text passed in as a VARCHAR2 string or a VARCHAR2 associative array may contain compile time errors. If errors are found when generating the post-processed source, the error message text will also appear at the end of the post-processed source text. In some cases, the preprocessing can be aborted because of errors. When this happens, the post-processed source text will appear to be incomplete and the associated error message can help indicate that an error has occurred during preprocessing.

• For subprograms of the second or third style, the source text can represent any arbitrary PL/SQL compilation unit. However, the source text of a valid PL/SQL compilation unit cannot include commonly used prefixes such as CREATE OR REPLACE. In general, the input source should be syntactically prepared in a way as if it were obtained from the ALL_SOURCE view. The following list gives some examples of valid initial syntax for some PL/SQL compilation units.

  anonymous block   (BEGIN | DECLARE) ...     
       package           PACKAGE name ...
       package body      PACKAGE BODY name ...
       procedure         PROCEDURE name ...
       function          FUNCTION name ...
  

  If the source text represents a named PL/SQL unit that is valid, that unit will not be created after its post-processed source text is generated.

• If the text of a wrapped PL/SQL unit is obtained from the ALL_SOURCE view, the keyword WRAPPED always immediately follows the name of the unit, as in this example:

  PROCEDURE "some proc" WRAPPED
  a000000
  b2
  ...
  

  If such source text is presented to a GET_POST_PROCESSED_SOURCE function or a PRINT_POST_PROCESSED_SOURCE procedure, the exception DBMS_PREPROCESSOR.WRAPPED_INPUT is raised.

Data structures

The DBMS_PREPROCESSOR package defines a table type.

Table types

SOURCE_LINES_T table type

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SOURCE_LINES_T table type

This table type stores lines of post-processed source text. It is used to hold PL/SQL source text both before and after it is processed. It is especially useful in cases in which the amount of text exceeds 32K.

Syntax

TYPE source_lines_t IS
    TABLE OF VARCHAR2(32767) INDEX BY BINARY_INTEGER;

Summary of DBMS_PREPROCESSOR subprograms

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GET_POST_PROCESSED_SOURCE function

This overloaded function returns the post-processed source text. The different functionality of each form of syntax is presented along with the definition.

Syntax

Returns post-processed source text of a stored PL/SQL unit:

DBMS_PREPROCESSOR.GET_POST_PROCESSED_SOURCE (
   object_type    IN VARCHAR2,
   schema_name    IN VARCHAR2,
   object_name    IN VARCHAR2)
  RETURN dbms_preprocessor.source_lines_t;

Returns post-processed source text of a compilation unit:

DBMS_PREPROCESSOR.GET_POST_PROCESSED_SOURCE (
   source        IN VARCHAR2)
  RETURN dbms_preprocessor.source_lines_t;

Returns post-processed source text of an associative array (index-by table) containing the source text of the compilation unit:

DBMS_PREPROCESSOR.GET_POST_PROCESSED_SOURCE (
   source        IN dbms_preprocessor.source_lines_t)
  RETURN dbms_preprocessor.source_lines_t;

Parameters

Return values

The function returns an associative array containing the lines of the post-processed source text starting from index 1.

Usage notes

• Newline characters are not removed.

• Each line in the post-processed source text is mapped to a row in the associative array.

• In the post-processed source, unselected text will have blank lines.

Exceptions

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PRINT_POST_PROCESSED_SOURCE procedure

This overloaded procedure calls DBMS_OUTPUT.PUT_LINE to let you view post-processed source text. The different functionality of each form of syntax is presented along with the definition.

Syntax

Prints post-processed source text of a stored PL/SQL unit:

DBMS_PREPROCESSOR.PRINT_POST_PROCESSED_SOURCE (
   object_type    IN VARCHAR2,
   schema_name    IN VARCHAR2,
   object_name    IN VARCHAR2);

Prints post-processed source text of a compilation unit:

DBMS_PREPROCESSOR.PRINT_POST_PROCESSED_SOURCE (
   source        IN VARCHAR2);

Prints post-processed source text of an associative array containing the source text of the compilation unit:

DBMS_PREPROCESSOR.PRINT_POST_PROCESSED_SOURCE (
   source        IN dbms_preprocessor.source_lines_t);

Parameters

Usage notes

The associative array may contain holes. Null elements are ignored when doing the concatenation.

Exceptions