(5)Physicaloptimization: During this phase, several operations areperformed. At first, the execution plans related to each SQL statementresulting from the logical optimization are generated. Then, based onstatistics found in the data dictionary or gathered through dynamic sampling, acost is associated ...
(2)解析游标(dbms_sql.parse) Parse cursor: A SQL statement is associated with thecursor. Its parsed representation that includes the execution plan (whichdescribes how the SQL engine will execute the SQL statement) is loaded in theshared pool, specifically, in the library cache. The structure i...
(2)解析游标(dbms_sql.parse) Parse cursor: A SQL statement is associated with thecursor. Its parsed representation that includes the execution plan (whichdescribes how the SQL engine will execute the SQL statement) is loaded in theshared pool, specifically, in the library cache. The structure i...
(2)解析游标(dbms_sql.parse) Parse cursor: A SQL statement is associated with thecursor. Its parsed representation that includes the execution plan (whichdescribes how the SQL engine will execute the SQL statement) is loaded in theshared pool, specifically, in the library cache. The structure i...
SQL cursors are rarely used in many organizations. In others, they are a last resort. And, in other groups, they are used regularly. Each of these camps, have different reasons for their stand on cursor usage in the DBMS. Regardless, they probably have a place in particular circumstances ...
dbms_xplan.display_cursor 1) sql tunning asking01 Note: example for reading execution plan, dbms_xplan.display_cursor('sql_id',child_number,'mode') 1@@@ sql script [oracle@station78 ~]$ sqlplus / as sysdba; SQL*Plus: Release 11.2.0.1.0 Production on Sun Mar 3 13:48:02 2013 ...
in parentheses. Note that this value is cumulated through the execution plan. In other words, the cost of parent operations contains the cost of their child operations. Time The estimated amount of time needed to execute the operation (HH:MM:SS). ...
首先,session1执行以下匿名块,该匿名块通过cursor取得t1表的所有数据,不过在open cursor后将暂停30秒,在这30秒中我们将在session2中删除t1表的所有数据: DECLARE CURSOR c IS SELECT deptno ,dname ,loc FROM t1; TYPE dept_tab IS TABLE OF c%ROWTYPE; l_depts dept_tab; BEGIN dbms_output.put_line('op...
Loops that iterate over SQL query results are quite common, both in application programs that run outside the DBMS, as well as User Defined Functions (UDFs) and stored procedures that run within the DBMS. It can be argued that set-oriented operations are more efficient and...
DBMS_OUTPUT.PUT_LINE(emp_job.employee_id||': '||emp_job.employee_name||' is a '||emp_job.job_id); FETCH refcur_emp INTO emp_job; END LOOP; END; / Query OK, 0 rows affected 200: Jennifer is a AD_ASST 202: Pat is a MK_REP ...