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. ...
Summary: in this tutorial, you will learn about PL/SQL cursor variables and how to manage cursor variables using REF CURSOR. Introduction to PL/SQL cursor variables A cursor variable is a variable that references a cursor. Unlike implicit and explicit cursors, a cursor variable is not tied ...
Global package variable g_ Local variable l_ Parameter p_ Cursor csr_ Record rec_ 保证所有变量只被赋值一次。每个变量的功能只有一个。尽可能不声明多余的变量,用只读的function代替,或作为实参传入function。因为作为参数在function中是只读的,不会担心值会被变更。去除多余的变量,也是重构的主要手段。 例子:1....
A cursor variable is a cursor that contains a pointer to a query result set. The result set is determined by execution of the OPEN FOR statement using the cursor variable.
--静态SQL:当一个SQL语句所在的代码块被编译时,这个语句就完全指定的或者是固定的。--动态SQL:如果一个SQL语句直到运行时刻才被构造出来并执行,这个语句就是动态SQL语句--结果集: sql语句所请求的行集的和,结果集中会被缓存在SGA以提升访问数据和修改数据的性能--隐式游标:每一个SQL DML语句或者SELECT INTO PL...
Specifies an identifier for a cursor variable that was previously declared within a PL/SQL context. FOR dynamic-string Specifies a string literal or string variable that contains a SELECT statement (without the terminating semicolon). The statement can contain named parameters, such as, for example...
open cursor---> parse---> bind variable---> execute---> close cursor; 对于delete操作只需要进行以下几个步骤: open cursor---> parse---> execute---> close cursor; 利用DBMS_SQL执行DDL语句: 1 2 3 4 5 6 7 8 9 10 CREATEORREPLACEPROCEDURECreateTable2 (tablename VARCHAR2) ...
procedure bind_variable(c in integer, name in varchar2, value):定义动态sql语句(DML)中所对应字段的值,c为游标,name为字段名称,value为字段的值; 以上是在程序中经常使用到的几个函数及过程,其他函数及过程请参照oracle所提供定义语句dbmssql.sql
CURSORc_salesISSELECT*FROMsalesORDERBYtotalDESC;Code language:PostgreSQL SQL dialect and PL/pgSQL(pgsql) The third variable is a cursor-based record namedc_sales. In the execution section, we perform the following: First, reset the credit limits of all customers to zero using anUPDATEstatement...
Oracle PL / SQL PL SQL Package Package with package level cursor variable SQL> SQL> CREATE TABLE employees 2 ( employee_id number(10) not null, 3 last_name varchar2(50) not null, 4 email varchar2(30), 5 hire_date date, 6 job_id varchar2(30), 7 department_id number(10), 8 ...