游标(cursor)是系统为用户开设的一个数据缓冲区,存放SQL语句的执行结果。每个游标区都有一个名字,用户可以用SQL语句逐一从游标中获取记录,并赋给主变量,交由主语言进一步处理。 游标是处理结果集的一种机制吧,它可以定位到结果集中的某一行,多数据进行读写,也可以移动游标定位到你所需要的行中进行操作数据。一般...
SQL is a set-based language, meaning operations are completed on all or rows of the result. However, there are times, when you want to do operation on a row by row basis. This is where cursors come in to play. What is a Database Cursor?
Structured Query Language (SQL) is a standardized language used in computer programming to handle databases. Learn about queries in SQL, and ponder an example of two tables to understand how to build a query. Updated: 12/19/2023 Structured Query Language A query is really a question or re...
在创建时,默认游标类型为pymysql.cursors.Cursor,可自行指定为其他游标类型,例如cur=conn.cursor(cursor=pymysql.cursor.DictCursor) pymysql.cursors.Cursor以元组形式返回sql执行结果 返回的结果中不含列名,仅包括数据 ((425, 'mike', '15166668765',0),) pymysql.cursors.DictCursor以列表字典 [dict, dict] 形...
'1899-12-30 00:00:00.000' appears in Date Time type columns. 'cannot access the file' when run as an SQL Agent Job (works when executed from BIDS) 'DECODE' is not a recognized built-in function name. 'DTEXEC.EXE' is not recognized as an internal or external command, 'gacutil' is ...
"Using Cursor Expressions" Multilevel Collections You can nest the collection types, for example to create aVARRAYof PL/SQL tables, aVARRAYofVARRAYs, or a PL/SQL table of PL/SQL tables. You can model complex data structures such as multidimensional arrays in a natural way. ...
I almost always use a cursor to loop through records when necessary. The cursor format is a lit...
A USE database statement is not allowed in a procedure, function or trigger. A week this year Against a week this time last year in SQL (NOT MDX) A WITH keyword and parenthesis are now required Accent Sensitivity Access Code - DELETE Statement with DISTINCTROW and T-SQL Access Now() vs...
Scalar functions can be used wherever an expression is valid. Categories of scalar functions Expand table Function categoryDescription Configuration Functions Return information about the current configuration. Conversion Functions Support data type casting and converting. Cursor Functions Return information ...
Tutorial #5:Subprograms: PL SQL Procedures And Functions With Examples Tutorial #6:PL SQL Collections: Nested Table, Associative Array And Varray Tutorial #7:PL SQL Cursor And Strings: Tutorial With Code Examples Tutorial #8:PL SQL Records Tutorial With Examples ...