This Oracle tutorial explains how to declare a cursor in Oracle / PLSQL with syntax and examples. A cursor is a SELECT statement that is defined within the declaration section of your PLSQL code.
Cursor without parameters (simplest) The basic syntax for a cursor without parameters is: CURSOR cursor_name IS SELECT_statement; 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 thi...
1. 确认错误信息的来源和上下文 该错误信息通常出现在使用数据库管理系统(如 PostgreSQL、Oracle、SQL Server 等)进行编程时,尝试在事务块外部声明游标(Cursor)的场景中。游标是用于逐行处理查询结果集的数据库对象,它必须在事务的上下文中声明和使用。 2. 解释“transaction blocks”的含义 “transaction blocks”指的...
DECLARE my_cursor CURSOR IS SELECT * FROM employees; END; 复制代码 异常:虽然Oracle SQL不直接支持异常的声明,但可以使用EXCEPTION关键字处理在程序执行过程中可能发生的异常情况。例如: DECLARE my_exception EXCEPTION; BEGIN -- some code that might raise an exception EXCEPTION WHEN my_exception THEN -- ...
/* TYPE c1 IS REF CURSOR; temp_cursor c1;*/ /* actmfile_rec temp_cursor%ROWTYPE;*/ begin /*del文章*/ sqlstr1:='delete from zs_articles where articleid='''||ArticleId||'''; EXECUTEIMMEDIATE sqlstr1intoArticleNum; /*del文章明细*/ sql...
procedure if exists overdueBooks // create procedure overdueBooks (in memberid INT)declarereturnCheck date;declareoverdueList varchar (100) default "";declarecursor_ 浏览0提问于2020-11-02得票数0 1回答 如果表为空,则选择表名 、、、 DECLARE@Footprint VARCHAR(200)DECLAREMY_CURSORCURSORFETCH NEXT FR...
The SQL standard only makes provisions for cursors in embeddedSQL. TheLightDBserver does not implement anOPENstatement for cursors; a cursor is considered to be open when it is declared. However,ECPG(Oracle Pro*c Compatible), the embedded SQL preprocessor forLightDB, supports the standard SQL ...
Oracle Supported PostgreSQL Supported SQL99 Syntax and Description TheDECLARE CURSORcommand works by specifying aSELECTstatement. Each row returned by theSELECTstatement may be individually retrieved and manipulated. TheDECLARE CURSORcommand also defines the characteristics of a server-side cursor. The chara...
游标声明:DECLARE cursor_name CURSOR FOR select_statement; 应用场景 数据处理:当需要对大量数据进行复杂处理时,可以使用存储过程和 DECLARE 来封装逻辑。 业务逻辑:将业务逻辑封装在存储过程中,可以简化应用程序的代码结构。 触发器:在数据库事件发生时自动执行的代码块,可以使用 DECLARE 来声明所需的变量和条件。
Oracle Declare语法还可以用来定义游标,游标可以用于查询数据,并对查询结果进行处理。游标的定义格式如下: Declare Cursor 游标名称 [参数列表] is SELECT语句; 其中,游标名称是用户自定义的游标名称,参数列表是可选项,用于传递参数给SELECT语句。SELECT语句用于查询数据,并返回游标结果集。 例如,下面是定义一个游标的示...