As you’ll see, most objects are defined with a variation of the CREATE command, such as CREATE TABLE or CREATE VIEW. The DROP command is used to delete an existing object (and all of the data it might contain). Examples include DROP TABLE or DROP INDEX. Because the command syntax is...
1. 查询 2. 创建 3. 删除 4. 使用 2、表操作-查询-创建 1. 查询 2. 创建 3、SQL数据类型 1. 数值类型 2. 字符串类型 3. 日期类型 4、表操作-修改-删除 5、图形化界面 启动和关闭mysql net startmysql80 net stop mysql80 DDL(data definition language数据定义语句) 1、数据库操作 1. 查询 查询...
Data Definition Language (DDL) Statements Data definition language (DDL) statements enable you to perform these tasks: Create, alter, and drop schema objects Grant and revoke privileges and roles Analyze information on a table, index, or cluster Establish auditing options Add comments to the...
sql语句-第一章-DDL(Data Definition language)- (!!!文中db1、db2等为数据库名,为了简化文本,,gbk是字符集,***在sql语句中的关键字推荐大家大写,但是在sqlyog中会自动将关键字转换为大写,后面不想码大写字母了,所以一律写成了小写。) 第一节:DDL操作数据库 1.1.1 创建数据库几种方式 --创建数据库:CREAT...
lAtomicityofupdates4Failuresmayleavedatabaseinaninconsistentstatewithpartialupdatescarriedout4Example:Transferoffundsfromoneaccounttoanothershouldeithercompleteornothappenatall lConcurrentaccessbymultipleusers4Concurrentaccessneededforperformance4Uncontrolledconcurrentaccessescanleadtoinconsistencies–Example:Twopeoplereadinga...
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...
to specify the database schema and adata manipulation languageto express database queries and updates. In practice, the data definition and data manipulation languages are not two separate languages; instead they simply form parts of a single database language, such as the widely usedSQLlanguage....
This might not matter if you create databases in SQL Database before you migrate, but if you're migrating T-SQL code that creates databases you should compare CREATE DATABASE (Azure SQL Database) with the SQL Server syntax at CREATE DATABASE (SQL Server T-SQL) to make sure all the ...
What's New and Enhanced in Transact-SQL (Transact-SQL) Sample Database Enhancements (Transact-SQL) Transact-SQL Data Types Database Console Commands (DBCC) (Transact-SQL) Data Definition Language (DDL) Statements (Transact-SQL) Data Definition Language (DDL) Statements (Transact-SQL) Transact-SQL...
SQL includes a sub-language for defining schemas, the data definition language (DDL), along with a sub-language for modifying data, the data manipulation language (DML). Both of these have roots in early CODASYL specifications. The third sub-language in SQL declares queries, through the SELECT...