Oracle Database need not verify thata cursor is in the cache because it cannot be deallocated while an applicationcursor associated with it is open.
The query associated with a cursor variable can reference any variable in its scope. Changing the values of the variables later does not change the result set. The following code opens a cursor variable for a query that references the variable factor. ...
(1)If CURSOR_SPACE_FOR_TIMEis set to false (the default), then a cursor can be deallocated from the library cache regardless ofwhether application cursors associated with its SQL statement are open.In this case, Oracle Database must verify that the cursor containing the SQLstatement is in th...
For example, you could define a cursor called c1 as below. CURSOR c1 IS SELECT course_number FROM courses_tbl WHERE course_name = name_in; The result set of this cursor is all course_numbers whose course_name matches the variable called name_in. ...
Starting from Oracle 9i, you can use SYS_REFCURSOR, which is a predefined weak typed REF CURSOR, to declare a weak REF CURSOR as follows: DECLARE c_customer SYS_REFCURSOR; Code language: PostgreSQL SQL dialect and PL/pgSQL (pgsql) PL/SQL cursor variable examples The following function get...
If SIMILAR is used, and if a histogram does exist, then the database does not treat the statement as if a bind variable were used.The same query for a different employee may not use the same plan. If you set CURSOR_SHARING,then Oracle recommends the FORCE setting unless you are in a...
cursor 游标,是ORACLE数据库中SQL解析和执行的载体,本质上是C语言中的一种结构structure. ORACLE数据库中cursor分类: shared cursor包括: parent cursor、child cursor session cursor包括: 隐式游标 implicit cursor、 显式游标 explicit cursor、 参考游标 ref cursor 两者关系是:一个session cursor只能对应一个shared...
Oracle里的cursor分为两种:一种是shared cursor,一种是session cursor。 1.1 Shared cursor 说明 sharedcursor就是指缓存在librarycache(SGA下的Shared Pool)里的一种library cache object,说白了就是指缓存在library cache里的sql和匿名pl/sql。 它们是Oracle缓存在librarycache中的几十种librarycache object之一,它所...
Alternatively, you can reopen the cursor variable, bind it to another query (the cursor of the current query is automatically closed), and repeat the preceding steps. Example: Use a cursor variable to fetch all rows from a record set in a loop manner...
Oracle笔记（八）、PL/SQL高级应用（游标、存储过程、函数、程序包） 一、游标 二、存储过程 三、函数 过程与函数的异同 四、程序包 一、游标 游标是一种PL/SQL控制结构，可以对SQL语句的处理进行显式控制，便于对表的数据逐条进行处理。 ps.当表中数据量大的时候，不建议使用游标（效率不高，耗费资源）...