DML (Data Manipulation Language) are SQL commands focused on handling data within the database, including most SQL statements. Let's look at some DML commands with a simple example for each command. i. INSERT I
TRANSACTION_SERIALIZABLE); Statement stmt = conn.createStatement(); int rows = stmt.executeUpdate("INSERT INTO city VALUES (3,'china',1,'cc')"); // 设置事务保存点 svpt = conn.setSavepoint(); rows = stmt.executeUpdate("UPDATE city set country = 'TAIWAN' WHERE id = 4"); // 提交事务...
Transaction Control Language (TCL) controls the time and effect of database transactions and monitors the database.GaussDB(DWS) uses the COMMIT or END statement to commit
看到很多人讨论SQL还分为四种类型,在这里知识普及一下,并总结下他们的区别吧。1. DDL – Data Definition Language数据库定义语言:定义数据库的结构。其主要命令有CREATE,ALTER,DROP等,下面用例子详解。该语言不需要commit,因此慎重。CREATE – to create objects in the database 在数据库创建对象例: CREATE DATA...
是指在TCL编程语言中,通过使用合适的语法和方法,从已定义的变量中获取其存储的值。TCL(Tool Command Language)是一种脚本语言,常用于快速开发应用程序、自动化任务和测试脚本。 在TCL中,可以使用以下语法从变量中获取值: 使用变量名:直接使用变量名即可获取其存储的值。例如,如果有一个名为"myVariable"的变量,可以...
Statement stmt = conn.createStatement(); int rows = stmt.executeUpdate("INSERT INTO city VALUES (3,'china',1,'cc')"); rows = stmt.executeUpdate("UPDATE city set country = 'TAIWAN' WHERE id = 4"); // 提交事务 conn.commit();
Statement stmt = conn.createStatement(); int rows = stmt.executeUpdate("INSERT INTO city VALUES (3,'china',1,'cc')"); // 设置事务保存点 svpt = conn.setSavepoint(); rows = stmt.executeUpdate("UPDATE city set country = 'TAIWAN' WHERE id = 4"); // 提交事务 conn.commit(); } catch...
数据库操作语言:SQL中处理数据库中的数据 其主要命令有SELECT,INSERT,UPDATE,DELETE等,这些例子大家常用就不一一介绍了。该语言需要commit。还有常用的 LOCK TABLE ,记得写过锁的博客 – 传送门 还有其他不熟悉的: CALL – 调用一个PL/SQL或Java子程序
Once a DDL statement is executed, it takes effect immediately in the database. Which means any changes done to the database using DDL command is permanent. Popular DDL commands are: CREATE, DROP, ALTER and TRUNCATE. a) CREATE:This command is used to create database and tables inside a da...
The switchingString is used in a switch statement; used between the different blocks by comparing to the matchString. You can have any number of matchString blocks within a switch. A switch statement can have an optional default block, which must appear at the end of the switch. The ...