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5.3 PLV: Top-Level Constants and Functions

The PLV (PL/Vision) package provides a single collection point for constants and basic functions used throughout the PL/Vision library of packages. See Chapter 6, PLV: Top-Level Constants and Functions for details.

5.3.1 PL/Vision constants

dbtab CONSTANT VARCHAR2(2) := 'DB';
pstab CONSTANT VARCHAR2(2) := 'PS';
file CONSTANT VARCHAR2(2) := 'F';
string CONSTANT VARCHAR2(2) := 'S';
stdout CONSTANT VARCHAR2(2) := 'SO';

Names of different repositories supported within PL/Vision. These are mostly used by PLVio and by users of PLVio to set up the source and target repositories for PL/SQL code.

c_datemask CONSTANT VARCHAR2(100) :=
'FMMonth DD, YYYY FMHH24:MI:SS'

The default date format mask for PL/Vision .

5.3.2 Anchoring datatypes

plsql_identifier VARCHAR2(100) := 'IRRELEVANT';
max_varchar2 VARCHAR2(32767) := 'IRRELEVANT';
vcmax_len CONSTANT INTEGER := 32767;

The plsql_identifier variable offers a standard format for the declaration of any variables that will hold PL/SQL identifiers, such as table and column names.

The max_varchar2 variable offers a standard format for the declaration of any variables that require the maximum possible size for VARCHAR2 variables, which is 32,767 bytes and also reflected by the value of the vcmax_len constant.

5.3.3 Setting the date format mask

PROCEDURE set_datemask (datemask_in IN VARCHAR2 := c_datemask);

Sets the string used as the default date format mask within PL/Vision.

FUNCTION datemask RETURN VARCHAR2;

Returns the string used as the default date format mask within PL/Vision.

5.3.4 Setting the NULL substitution value

PROCEDURE set_nullval (nullval_in IN VARCHAR2);

Sets the string used as the substitution value for NULLs within PL/Vision.

FUNCTION nullval RETURN VARCHAR2;

Returns the current NULL substitution value.

5.3.5 Assertion routines

assertion_failure EXCEPTION;

Exception raised by the various assertion routines when the assertion fails.

PROCEDURE assert (bool_in IN BOOLEAN, stg_in IN VARCHAR2 := NULL);

Does nothing if the Boolean argument evaluates to TRUE. Otherwise (for FALSE or NULL), it raises the assertion_failure exception and displays the message.

This same behavior holds for the other assertion routines shown below.

PROCEDURE assert_notnull
(val_in IN VARCHAR2, stg_in IN VARCHAR2 := NULL);
PROCEDURE assert_notnull
(val_in IN DATE, stg_in IN VARCHAR2 := NULL);
PROCEDURE assert_notnull
(val_in IN NUMBER, stg_in IN VARCHAR2 := NULL);
PROCEDURE assert_notnull
(val_in IN BOOLEAN, stg_in IN VARCHAR2 := NULL);

Overloadings for the NOT NULL assertion logic.

PROCEDURE assert_inrange
(val_in IN DATE,
start_in IN DATE := SYSDATE, end_in IN DATE := SYSDATE+1,
stg_in IN VARCHAR2 := NULL, truncate_in IN BOOLEAN := TRUE);
PROCEDURE assert_inrange
(val_in IN NUMBER, start_in IN NUMBER, end_in IN NUMBER,
stg_in IN VARCHAR2 := NULL);

Overloadings of "in range" assertions for both date and numeric information.

5.3.6 Miscellaneous programs

FUNCTION boolstg (bool_in IN BOOLEAN, stg_in IN VARCHAR2 := NULL)
RETURN VARCHAR2;

Returns a string representing the value of the Boolean argument: TRUE if the Boolean argument is TRUE, FALSE if FALSE, and NULL if NULL.

FUNCTION errm (code_in IN INTEGER := SQLCODE) RETURN VARCHAR2;

Returns the error message provided by SQLERRM. Encapsulation inside this function allows SQLERRM to be referenced inside a SQL statement.

FUNCTION now RETURN VARCHAR2;

Returns the current date and time using the current PL/Vision date format mask.

PROCEDURE pause (secs_in IN INTEGER);

Pauses your PL/SQL program for the specified number of seconds.


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