Oracle9i笔记1(12)

新DML命令 Merge 格式 DECLARE

V_EMPNO EMPLOYEES.EMPLOYEE_ID%TYPE :=100; BEGIN

MERGE INTO copy_emp c USING employees e

ON (c.employee_id =v_empno) WHEN MATCHED THEN UPDATE SET

c.first_name = e.first_name, st_name =st_name, c.email =e.email, ……………

WHEN NOT MATCHED THEN

INSERT VALUES(e.employee_id,e.first_name,st_name,e.email….); End; 混合表

Implicit cursor oracle server在內存上自動創建一個用來執行命令的內存區域。 Explicit cursor 自己申明定義創建的 cursor。

SQL Cursor Attributes 游標特性

Using SQL cursor attributes, you can test the outcome of you SQL statements. 可以查驗SQL語句結果。

SQL%ROWCOUNT: Number of rows affected by the most recent SQL statement(an integer value)

SQL%FOUND: Boolean attribute that evaluates to true if the most recent SQL statement affects one or more rows

SQL%NOTFOUND: Boolean attribute that evaluates to true if the most recent SQL statement does not affect any rows

SQL%ISOPEN: Always evaluates to false because PL/SQL closes implicit cursors immediately after they are executed.

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