Oracle Database need not verify thata cursor is in the cache because it cannot be deallocated while an applicationcursor associated with it is open.
FETCH emp_cursor BULK COLLECT INTO emp_array LIMIT &rows; FOR i IN 1..emp_array.COUNT LOOP dbms_output.put_line('姓名:'||emp_array(i).ename ||',工资:'||emp_array(i).sal); END LOOP; EXIT WHEN emp_cursor%NOTFOUND; END LOOP; CLOSE emp_cursor; END; / --- 15-14:使用cursor表...
When Oracle Database executes a SQL statement, it stores the result set and processing information in an unnamedprivate SQL area. A pointer to this unnamed area, called acursor, lets youretrieve the rows of the result set one at a time.Cursor attributesreturn information about the state of t...
CURSOR—Oracle 游标 (cursor)知识 Library cache:主要作用是缓存刚刚执行过的sql语句和PL/SQL语句(如存储过程、函数、包、触发器)锁对应的执行计划、解析树、Pcode/Mcode等对象,当同样的SQL语句和PL/SQL语句再次被执行时,就可以例如已缓存再Library Cache中的那些相关对象而无需再次从头开始解析,这样就提高了这些...
在Oracle数据库里,任意一个目标sql一定会同时对应两个shared cursor。Parent cursor会存储该sql的文本,sql真正的可以被重用的解析树和执行计划则存储在child cursor。 SQL> select empno,ename from emp; SQL> select sql_text,sql_id,version_count from v$sqlarea where sql_text like'select empno,ename from ...
to the mutex then only one session can actually increment (or decrement) the reference count at a time.A wait on "cursor: pin S" thus occurs if a session cannot make that atomic change immediately due to other concurrent requests.Mutexes are local to the current instance in RAC environments...
Modifications to the database during a sequential scan will be reflected in the scan; that is, records inserted behind a cursor will not be returned while records inserted in front of a cursor will be returned. Method Summary void close() Discards the cursor. int count() Returns a count...
在Oracle数据库里,任意一个目标sql一定会同时对应两个shared cursor。Parent cursor会存储该sql的文本,sql真正的可以被重用的解析树和执行计划则存储在child cursor。 SQL> select empno,ename from emp; SQL> select sql_text,sql_id,version_count from v$sqlarea where sql_text like'select empno,ename from ...
Return a count of the number of data items for the key to which the cursor refers. OperationStatus delete() Delete the key/data pair to which the cursor refers. Cursor dup(boolean samePosition) Creates a new cursor that uses the same transaction and locker ID as the original cursor. ...
COUNT(*)ASSTAFFFROMemp_plGROUPBYdeptno)t2WHEREt1.deptno=t2.deptnoANDt2.staff>1;...