Oracle Built−in Packages- P93 ppsx

9.2.3.5.1 Restrictions This program asserts the following purity level with the RESTRICT_REFERENCES pragma: PRAGMA RESTRICT_REFERENCESCAST_TO_RAW, WNDS, RNDS, WNPS, RNPS; 9.2.3.5.2 Examp

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r2 Raw string to XOR with r1

9.2.3.4.1 Restrictions

This program asserts the following purity level with the RESTRICT_REFERENCES pragma:

PRAGMA RESTRICT_REFERENCES(BIT_XOR, WNDS, RNDS, WNPS, RNPS);

9.2.3.4.2 Example

To toggle a bit (if it is off, turn it on, and if it is on, turn it off) in a bit flag variable using a bitmask, use the BIT_XOR function as follows:

DECLARE

fourteenth VARCHAR2(8);

fifteenth VARCHAR2(8);

twentieth VARCHAR2(8);

mask RAW(4);

bitfield1 VARCHAR2(8);

bitfield2 VARCHAR2(8);

BEGIN

/* set the bitfield for the 15th through 18th */

bitfield1 := '0003C000';

/* set the bitfield for the 26st */

bitfield2 := '02000000';

/* set the mask for the 14th */

fourteenth := '00002000';

fifteenth := '00004000';

twentieth := '00080000';

/* merge the masks for the 14th, 15th and 20th */

mask := UTL_RAW.BIT_OR (HEXTORAW (fourteenth),HEXTORAW (fifteenth));

mask := UTL_RAW.BIT_OR (mask, HEXTORAW (twentieth));

/* check to see IF the bitfields have the 14th or 20th set */

IF UTL_RAW.BIT_AND (mask, HEXTORAW (bitfield1)) = '00000000' THEN

DBMS_OUTPUT.PUT_LINE ('bitfield1 is not set');

ELSE

DBMS_OUTPUT.PUT_LINE ('bitfield1 is set');

END IF;

ELSE

END IF;

/* toggle bit 15 in the mask */

mask := UTL_RAW.BIT_XOR (mask, HEXTORAW (fifteenth));

/* check to see IF the bitfield1 has the 14th, 15th, or 20th set */

ELSE

END IF;

END;

/

This is the output from the previous example:

bitfield1 is set

bitfield2 is not set

bitfield1 is not set

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9.2.3.5 The UTL_RAW.CAST_TO_RAW function

The CAST_TO_RAW function converts the VARCHAR2 input string into a raw datatype The data is not altered; only the data type is changed This is essentially a VARCHAR2_to_RAW function,

FUNCTION UTL_RAW.CAST_TO_RAW

(c IN VARCHAR2)

RETURN RAW;

where c is the text string that should be converted to a raw datatype

PRAGMA RESTRICT_REFERENCES(CAST_TO_RAW, WNDS, RNDS, WNPS, RNPS);

9.2.3.5.2 Example

For an example of CAST_TO_RAW, see "Section 9.2.3.15, "The UTL_RAW.TRANSLATE function"" later

in this chapter

9.2.3.6 The UTL_RAW.CAST_TO_VARCHAR2 function

The CAST_TO_VARCHAR2 function converts the raw input string into a VARCHAR2 datatype The data is not altered; only the data type is changed The current NLS language is used The specification is,

FUNCTION UTL_RAW.CAST_TO_VARCHAR2

(r IN RAW)

RETURN VARCHAR2;

where r is the raw string that should be converted into a VARCHAR2

PRAGMA RESTRICT_REFERENCES(CAST_TO_VARCHAR2, WNDS, RNDS, WNPS, RNPS);

9.2.3.6.2 Example

The data dictionary views USER_TAB_COLUMNS, ALL_TAB_COLUMNS, and DBA_TAB_COLUMNS have the first 32 bytes of the lowest and highest data values for each column in analyzed tables

Unfortunately, this data is of data type RAW and not very readable by humans The CAST_TO_VARCHAR2 function can be used on character datatype columns to see these data in more readable form

SELECT column_name, UTL_RAW.CAST_TO_VARCHAR2(low_value)

,UTL_RAW.CAST_TO_VARCHAR2(high_value)

FROM user_tab_columns

WHERE table_name = 'FOO_TAB'

AND column_name = 'VCHAR1'

9.2.3.7 The UTL_RAW.COMPARE function

The COMPARE function does a binary compare of the two raw input strings and returns the number of the first byte position where the two strings differ If the two strings are identical, a zero is returned If the two input strings are different lengths, then the pad character is repeatedly appended to the shorter string,

extending it to the length of the longer string The default pad character is 0x00 (binary zero)

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FUNCTION UTL_RAW.COMPARE

(r1 IN RAW

,r2 IN RAW

,pad IN RAW DEFAULT NULL)

RETURN NUMBER;

The parameters for this program are summarized in this table

Parameter Description

r1 The first input string to compare

r2 The second input string to compare

pad The single character used to right pad the shorter of two unequal length strings

PRAGMA RESTRICT_REFERENCES(COMPARE, WNDS, RNDS, WNPS, RNPS);

9.2.3.7.2 Example

Here is an example of the COMPARE function:

DECLARE

r_string1 RAW(16);

r_string2 RAW(16);

diff_position INTEGER;

BEGIN

r_string1 := UTL_RAW.CAST_TO_RAW('test string1');

r_string2 := UTL_RAW.CAST_TO_RAW('test string2');

diff_position := UTL_RAW.COMPARE(r_string1,r_string2);

DBMS_OUTPUT.PUT_LINE (

'r_string1='|| UTL_RAW.CAST_TO_VARCHAR2(r_string1));

'r_string2='|| UTL_RAW.CAST_TO_VARCHAR2(r_string2));

DBMS_OUTPUT.PUT_LINE ('diff_position='|| diff_position);

END;

/

Sample output follows:

r_string1=test string1

r_string2=test string2

diff_position=12

9.2.3.8 The UTL_RAW.CONCAT function

The CONCAT function is used to concatenate a set of 12 raw strings into a single raw string The size of the concatenated result must not exceed 32K or the procedure will raise the ORA−6502 exception

FUNCTION UTL_RAW.CONCAT

(r1 IN RAW DEFAULT NULL

,r2 IN RAW DEFAULT NULL

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,r12 IN RAW DEFAULT NULL)

RETURN RAW;

r1 First piece of raw data to be concatenated

r2 Second piece of raw data to be concatenated

r3 Third piece of raw data to be concatenated

r4 Fourth piece of raw data to be concatenated

r5 Fifth piece of raw data to be concatenated

r6 Sixth piece of raw data to be concatenated

r7 Seventh piece of raw data to be concatenated

r8 Eighth piece of raw data to be concatenated

r9 Ninth piece of raw data to be concatenated

r10 Tenth piece of raw data to be concatenated

r11 Eleventh piece of raw data to be concatenated

r12 Twelfth piece of raw data to be concatenated

9.2.3.8.1 Exceptions

The VALUE_ERROR exception (ORA−6502) is raised if the returned raw string exceeds 32K The

documentation from Oracle 7.3 and 8.0 indicates that this is to be revised in a future release, so don't count on

this exception to remain unchanged

PRAGMA RESTRICT_REFERENCES(CONCAT, WNDS, RNDS, WNPS, RNPS);

9.2.3.8.3 Example

For an example of CONCAT, see the example for TRANSLATE

9.2.3.9 The UTL_RAW.CONVERT function

The CONVERT function converts the input raw string r from one installed NLS character set to another installed NLS character set Here's the specification:

FUNCTION UTL_RAW.CONVERT

(r IN RAW

,to_charset IN VARCHAR2

,from_charset IN VARCHAR2)

RETURN RAW;

Parameters are summarized in the following table

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r The raw string to be converted

to_charset The name of the output NLS character set

from_charset The name of the input NLS character set

The VALUE_ERROR exception (ORA−6502) is raised if the input raw string is missing, NULL, or has zero length This exception is also raised if the from_charset or to_charset parameters are missing, NULL, zero

length, or name an invalid character set The documentation from both Oracle 7.3 and 8.0 indicates that this is

to be revised in a future release, so don't count on this exception to remain unchanged.

PRAGMA RESTRICT_REFERENCES(CONVERT, WNDS, RNDS, WNPS, RNPS);

9.2.3.10 The UTL_RAW.COPIES function

The COPIES function concatenates the input raw string r, n number of times Here's the specification:

FUNCTION UTL_RAW.COPIES

(r IN RAW

,n IN NUMBER)

RETURN RAW;

r The input raw string that is to be copied

n The number of copies of the input string to make (must be positive)

The VALUE_ERROR exception (ORA−6502) is raised if the input raw string r is missing, NULL, or has zero length This exception is also raised if the input number of copies n is less than 1 (n < 1) The documentation

from both Oracle 7.3 and 8.0 indicates that this is to be revised in a future release, so don't count on this

exception to remain unchanged

PRAGMA RESTRICT_REFERENCES(COPIES, WNDS, RNDS, WNPS, RNPS);

9.2.3.10.3 Example

Here is an example of the COPIES function:

DECLARE

r_string1 RAW(64);

r_repeat RAW(16);

BEGIN

r_repeat := UTL_RAW.CAST_TO_RAW('Test ');

r_string1 := UTL_RAW.COPIES(r_repeat,4);

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