在PL/SQL 编程中嵌套 IF-ELSE 语句,这意味着您可以使用一个 IF 要么ELSE IF 在另一个内部声明 IF 要么ELSE IF 声明。 句法 IF( boolean_expression 1)THEN -- executes when the boolean expression 1 is true IF(boolean_expression 2) THEN -- executes when the boolean expression 2 is true sequence...
When an applicationdevelopment tool processes PL/SQL units, it passes them to its local PL/SQLengine. If a PL/SQL unit contains no SQL statements, the local engine processesthe entire PL/SQL unit. This is useful if the application development tool canbenefit from conditional and iterative contr...
this statement is equivalent to nested IF...THEN...ELSE...IF...THEN statements, but only one END IF is needed. The following example uses an IF...THEN...ELSIF...ELSE statement to count the number of employees by compensation, in steps of $25,000. ...
When an applicationdevelopment tool processes PL/SQL units, it passes them to its local PL/SQLengine. If a PL/SQL unit contains no SQL statements, the local engine processesthe entire PL/SQL unit. This is useful if the application development tool canbenefit from conditional and iterative contr...
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PL/SQL详细介绍,设置oracle相关 1. 实现参照完整性 指若两个表之间具有主从关系(即主外键关系),当删除主表数据时,必须确保相关的从表数据已经被删除. 当修改主表的主键列数据时,必须确保相关从表数据已经被修改.为了实现级联删除,可在定义外部键约束时指定ON DELETE CASCADE关键字...
PL/SQL procedure successfully completed. Try it Yourself In this chapter you've learned about different types of IF statements. You've also learned that all these different IF statements can be nested inside one another. Here are some exercises that will help you test the depth of your underst...
formal parameters. If necessary, before assigning the value of an actual parameter to a formal parameter, PL/SQL converts the datatype of the value. For example, if you pass a number when the procedure expects a string, PL/SQL converts the parameter so that the procedure receives a string...
PL/SQL 允许在另一个循环中使用一个循环。以下部分显示了一些示例来说明这个概念。 PL/SQL 中嵌套基本 LOOP 语句的语法如下: LOOP Sequence of statements1 LOOP Sequence of statements2 END LOOP; END LOOP; 复制 PL/SQL 中嵌套 FOR LOOP 语句的语法如下: FOR counter1 IN initial_value1 .. final_...
put_line(i || ' is prime'); END IF; i := i + 1; exit WHEN i = 50; END LOOP; END; / When the above code is executed at the SQL prompt, it produces the following result −2 is prime 3 is prime 5 is prime 7 is prime 11 is prime 13 is prime 17 is prime 19 is ...