DBMS_DB_VERSION

55 DBMS_DB_VERSION

The DBMS_DB_VERSION package specifies the Oracle version numbers and other information useful for simple conditional compilation selections based on Oracle versions.

55.1 DBMS_DB_VERSION Overview

The DBMS_DB_VERSION package specifies the Oracle version numbers and other information useful for simple conditional compilation selections based on Oracle versions.

The package for the Oracle Database 21c version is shown below.

PACKAGE DBMS_DB_VERSION IS
   VERSION CONSTANT PLS_INTEGER := 21; -- RDBMS version number
   RELEASE CONSTANT PLS_INTEGER := 0;  -- RDBMS release number
   ver_le_9_1    CONSTANT BOOLEAN := FALSE;
   ver_le_9_2    CONSTANT BOOLEAN := FALSE;
   ver_le_9      CONSTANT BOOLEAN := FALSE;
   ver_le_10_1   CONSTANT BOOLEAN := FALSE;
   ver_le_10_2   CONSTANT BOOLEAN := FALSE;
   ver_le_10     CONSTANT BOOLEAN := FALSE;
   ver_le_11_1   CONSTANT BOOLEAN := FALSE;
   ver_le_11_2   CONSTANT BOOLEAN := FALSE;
   ver_le_11     CONSTANT BOOLEAN := FALSE;
   ver_le_12_1   CONSTANT BOOLEAN := FALSE;
   ver_le_12_2   CONSTANT BOOLEAN := FALSE;
   ver_le_12     CONSTANT BOOLEAN := FALSE;
   ver_le_18     CONSTANT BOOLEAN := FALSE;
   ver_le_19     CONSTANT BOOLEAN := FALSE;
   ver_le_20     CONSTANT BOOLEAN := FALSE;
   ver_le_21     CONSTANT BOOLEAN := TRUE;
END DBMS_DB_VERSION;

The boolean constants follow a naming convention. Each constant gives a name for a boolean expression. For example:

VER_LE_9_1 represents version <= 9 and release <= 1
VER_LE_10_2 represents version <= 10 and release <= 2
VER_LE_10 represents version <= 10

A typical usage of these boolean constants is:

$IF DBMS_DB_VERSION.VER_LE_10 $THEN
   version 10 and earlier code
$ELSIF DBMS_DB_VERSION.VER_LE_11 $THEN
   version 11 code
$ELSE
   version 12 and later code
$END

This code structure will protect any reference to the code for version 12. It also prevents the controlling package constant DBMS_DB_VERSION.VER_LE_11 from being referenced when the program is compiled under version 10. A similar observation applies to version 11. This scheme works even though the static constant VER_LE_11 is not defined in version 10 database because conditional compilation protects the $ELSIF from evaluation if DBMS_DB_VERSION.VER_LE_10 is TRUE.

55.2 DBMS_DB_VERSION Constants

The DBMS_DB_VERSION package contains different constants for different Oracle Database releases.

The Oracle Database 21c version of the DBMS_DB_VERSION package uses the constants shown in the following table.

Table 55-1 DBMS_DB_VERSION Constants

Name	Type	Value	Description
`VERSION`	`PLS_INTEGER`	`21`	Current version
`RELEASE`	`PLS_INTEGER`	`0`	Current release
`VER_LE_9`	`BOOLEAN`	`FALSE`	Version <= 9
`VER_LE_9_1`	`BOOLEAN`	`FALSE`	Version <= 9 and release <= 1
`VER_LE_9_2`	`BOOLEAN`	`FALSE`	Version <= 9 and release <= 2
`VER_LE_10`	`BOOLEAN`	`FALSE`	Version <= 10
`VER_LE_10_1`	`BOOLEAN`	`FALSE`	Version <= 10 and release <= 1
`VER_LE_10_2`	`BOOLEAN`	`FALSE`	Version <=10 and release <= 2
`VER_LE_11`	`BOOLEAN`	`FALSE`	Version <= 11
`VER_LE_11_1`	`BOOLEAN`	`FALSE`	Version <=11 and release <= 1
`VER_LE_11_2`	`BOOLEAN`	`FALSE`	Version <=11 and release <= 2
`VER_LE_12`	`BOOLEAN`	`FALSE`	Version <=12
`VER_LE_12_1`	`BOOLEAN`	`FALSE`	Version <=12 and release <= 1
`VER_LE_12_2`	`BOOLEAN`	`FALSE`	Version <=12 and release <= 2
`VER_LE_18`	`BOOLEAN`	`FALSE`	Version <=18
`VER_LE_19`	`BOOLEAN`	`FALSE`	Version <=19
`VER_LE_20`	`BOOLEAN`	`FALSE`	Version <=20
`VER_LE_21`	`BOOLEAN`	`TRUE`	Version <=21

55.3 DBMS_DB_VERSION Examples

This example uses conditional compilation to guard new features.

CREATE OR REPLACE PROCEDURE whetstone IS
 
 -- Notice that conditional compilation constructs
 -- can interrupt a regular PL/SQL statement.
 -- You can locate a conditional compilation directive anywhere
 -- there is whitespace in the regular statement.

 SUBTYPE my_real IS
    $IF DBMS_DB_VERSION.VER_LE_9 $THEN NUMBER
                                 $ELSE BINARY_DOUBLE
    $END;

 t  CONSTANT my_real := $IF DBMS_DB_VERSION.VER_LE_9 $THEN 0.499975 
                                                     $ELSE 0.499975d 
                        $END;

 t2 CONSTANT my_real := $if DBMS_DB_VERSION.VER_LE_9 $THEN 2.0
                                                     $ELSE 2.0d
                        $END;

 x  CONSTANT my_real := $IF DBMS_DB_VERSION.VER_LE_9 $THEN 1.0
                                                     $ELSE 1.0d
                        $END;

 y  CONSTANT my_real := $IF DBMS_DB_VERSION.VER_LE_9 $THEN 1.0
                                                     $ELSE 1.0d
                        $END;
 
 z  MY_REAL;
 
 PROCEDURE P(x IN my_real, y IN my_real, z OUT NOCOPY my_real) IS
   x1 my_real;
   y1 my_real;
 BEGIN
   x1 := x;
   y1 := y;
   x1 := t * (x1 + y1);
   y1 := t * (x1 + y1);
   z := (x1 + y1)/t2;
 END P;
BEGIN
 P(x, y, z);
 DBMS_OUTPUT.PUT_LINE ('z = '|| z);
END whetstone;
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