Adding a column to a table is common task for DBAs. You can add a column to a table which is a nullable column or which has default values. But are these two operations are similar internally and which method is optimal? Let us start this with an example. I created a database and a...
- **语法**: `ALTER TABLE table_name ADD PRIMARY KEY (column_name);` - 示例: `ALTER TABLE tabname ADD PRIMARY KEY (col);` - **删除主键** - **语法**: `ALTER TABLE table_name DROP PRIMARY KEY;` - ... mysql的常用sql语句.pdf ALTER TABLE table_name ADD CONSTRAINT fk_name FOREI...
ScriptLoader:sql配置文件加载解析器,封装于SqlToyContext中。sql文件严格按照*.sql.xml规则命名。 TranslateManager:缓存翻译管理器,用于加载缓存翻译的xml配置文件和缓存实现类,sqltoy提供了接口并提供了默认基于ehcache的本地缓存实现,这样效率是最高的,而redis这种分布式缓存IO开销太大,缓存翻译是一个高频度的调用,一般...
Script Library Add columns to table with script
using Microsoft.SqlServer.Dac.CodeAnalysis; using Microsoft.SqlServer.Dac.Model; using Microsoft.SqlServer.TransactSql.ScriptDom; using System; using System.Collections.Generic; using System.Globalization; namespace SampleRules { class AvoidWaitForDelayRule {} } 在AvoidWaitForDelayRule 类声明中,...
The below script creates a table and then adds a new column with a default value. DROP TABLE tblPlanDiff GO CREATE TABLE tblPlanDiff(Sno int identity,Col_1 int,Col_2 int) GO ALTER TABLE tblplandiff ADD Col_3 int NOT NULL DEFAULT(100) ...
ALTER TABLE语句修改表定义;它可以添加元素、删除元素或修改现有元素。在每个ALTER TABLE语句中只能执行一种类型的操作。 RENAME可以重命名表,也可以使用ALTER COLUMN或MODIFY语法重命名表中的现有列。 Add可以向表中添加多个列和/或约束。只需指定一次ADD关键字,后跟一个逗号分隔的列表。可以使用逗号分隔的列表向表中...
AlterTableAlterColumnOption Enum Reference Feedback Definition Namespace: Microsoft.SqlServer.TransactSql.ScriptDom Assembly: Microsoft.SqlServer.TransactSql.ScriptDom.dll Package: Microsoft.SqlServer.TransactSql.ScriptDom v161.8901.0 The options for alter column version of alter table statement. Add...
show tables;show databases;show partitions;show functions;describe extended table_name dot col_name; DDL(Data Defination Language):数据库定义语言 建表: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 CREATE[EXTERNAL]TABLE[IFNOTEXISTS]table_name[(col_name data_type[COMMENTcol_comment],...)][...
The following script makes use of SQL Server ALTER TABLE ADD Column (Status in our case) statement to add a column named Status with default constraint. 1 2 3 ALTER TABLE SampleTable ADD Status CHAR(5000) DEFAULT 'INC' WITH VALUES When the column is added as above, the Status column...