в 13:45, 26 мая 2010

2010-05-26T13:45:46Z

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2010-05-26T10:09:00Z

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== EMPTY_BLOB() function==



<source lang="sql">
SQL>
SQL> CREATE TABLE myBlob
2 (id NUMBER PRIMARY KEY,
3 blob_data BLOB);
Table created.
SQL>
SQL>
SQL> UPDATE myBlob
2 SET blob_data =EMPTY_BLOB()
3 WHERE id =1;
0 rows updated.
SQL>
SQL> drop table myBlob;
Table dropped.
SQL>
SQL></source>

== Insert a new row using EMPTY_CLOB() to create a LOB locator==



<source lang="sql">
SQL>
SQL> CREATE TABLE facebook (
2 name VARCHAR2(80),
3 photo BLOB,
4 directions CLOB,
5 description NCLOB,
6 web_page BFILE);
Table created.
SQL>
SQL> CREATE DIRECTORY bfile_data AS "c:\xxx";
Directory created.
SQL> Demonstrates the difference between an empty LOB and a NULL LOB
SP2-0734: unknown command beginning "Demonstrat..." - rest of line ignored.
SQL> DECLARE
2 directions CLOB;
3 BEGIN
4
5 DELETE FROM facebook WHERE name="Falls";
6
7
8 INSERT INTO facebook
9 (name,directions)
10 VALUES ("Falls",EMPTY_CLOB());
11
12 SELECT directions
13 INTO directions
14 FROM facebook
15 WHERE name="Falls";
16
17 IF directions IS NULL THEN
18 DBMS_OUTPUT.PUT_LINE("directions is NULL");
19 ELSE
20 DBMS_OUTPUT.PUT_LINE("directions is not NULL");
21 END IF;
22
23 DBMS_OUTPUT.PUT_LINE("Length = "|| DBMS_LOB.GETLENGTH(directions));
24 END;
25 /
PL/SQL procedure successfully completed.
SQL>
SQL>
SQL> drop table facebook;
Table dropped.
SQL> drop directory bfile_data;
Directory dropped.</source>

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Oracle PL/SQL Tutorial/Large Objects/EMPTY BLOB - История изменений

в 13:45, 26 мая 2010

Admin: 1 версия