SQL commands are categorized into 5 categories. DDL - Data Definition Language DQL - Data Query Language DML - Data Manipulation Language DCL - Data Control Language TCL - Transaction Control Language DDL (Data Definition Language) Command in SQL DDL or Data definition language is actually the def...
启动和关闭mysqlnet start mysql80net stop mysql80DDL(data definition language 数据定义语句)1、数据库操作1. 查询查询所有数据库: SHOW DATABASES;查询当前数据库:SELECT DATABASE();2. 创建 CREATE DATABA…
此处为默认账户(default),即当前登录到SQL Server的账户。用户也可以修改此处的值,如果使用Windows系统身份验证登录,这里的值将会是系统用户ID;如果使用SQL Server 身份验证登录,这里的值将会是连接到服务器的ID.(3)使用全文检索:如果想让数据库具有搜索特定内容的字段,需要选择此选项。(4)逻辑名称:引用文件时使用的...
Data Definition Language (DDL) commands are used for defining the database structure or schema. Let's look at some DDL commands with a simple example for each command. i. CREATE In SQL, theCREATE TABLEcommand is used to create a new table in the database. For example, CREATETABLEProducts...
DDL (Data Definition Language) DML (Data Manipulation Language) DCL (Data Control Language) TCL (Transactional Control Language) This article only covers the SQL DDL commands. SQL DDL commands The DDL commands in SQL are used to create database schema and to define the type and structure of ...
AllALTERcommands in SQL follow a similar structure, making SQL a natural programming language to learn and master. RENAME command in ALTER Whenever I need to change a column name, I use theRENAMEcommand inALTERas follows: ALTERTABLEtable_nameRENAMECOLUMNold_column_nameTOnew_column_name; ...
CREATEDATABASEDB3CHARACTERSETGBK;#指定数据库的字符集 CREATEDATABASEIFNOTEXISTSDB4CHARACTERSETGBK;#创建db4数据库,判断是否存在,并制定字符集为gbk 2、R(Retrieve):查询 SHOWDATABASES;#查询所有数据库 查询数据库 SHOWCREATEDATABASEtest;-- 查询某个数据库的创建语句(字符集) ...
ENCRYPTED= <true | false> - this flag controls whether encryption is enabled The CREATE TABLE command creates a new GridGain cache and defines a SQL table on top of it. The cache stores the data in the form of key-value pairs while the table allows processing the data with SQL queries....
SQL > Data Definition Language - DDL Data Definition Language (DDL) is a part of SQL that is used to create, modify, and delete database objects such as table, view, and index, and to manage access privileges to these objects. Below are the most common DDL commands: ...
SQL/数据定义语言DDL(Data Definition Language) DDL主要是用在定义或改变,表的结构,数据类型,表之间的链接和约束等初始化工作上 如:CREATE、ALTER、DROP 库和表的管理、数据类型、约束、标识列 /*数据定义语言 库和表的管理 一、库的管理 创建、修改、删除...