Define a primary key in the SQL Server Database Engine by using SQL Server Management Studio or Transact-SQL.
Creating a primary key in an existing table requiresALTERpermission on the table. Use SQL Server Management Studio In Object Explorer, right-click the table to which you want to add a unique constraint, and selectDesign. InTable Designer, select the row selector for the database column you ...
The primary key is always active. SQL Server keeps the table sorted in primary key order and rejects records with duplicate values in primary key fields. That's why the values in the primary key must always be unique. It's not the value in each field in the primary key that must be u...
用SQL语句创建表,使用语句 CREATE TABLE 。对列的约束主要有NOT NULL ,UNIQUE ,PRIMARY KEY ,FOREIGN KEY 等。定义表的删除与更新操作的完整性约束,主要有四种模式:NO ACTION ,CASCADE ,SET NULL ,SET DEFAULT 。检查列的取值范围可以用 CHECK 约束。设定列的默认取值,可以用DEFAULT 短语。正确 错误判断题 正确...
Oracle PL/SQL:CREATE TABLE statement: create a table with primary key.CREATE TABLE statement can be used to create table objects in database. It is possible to add constraints like primary key ,foreign key while table creation.Primary key is the unique identifier for a row of data.One ...
obclient>CREATETABLEt1(c1INTPRIMARYKEY,c2INT)PARTITIONBYHASH(c1)PARTITIONS8;Query OK,0rowsaffected 创建一级分区为 Range 分区,二级分区为 Key 分区的表。 obclient>CREATETABLEt1(c1INT,c2INT,c3INT)PARTITIONBYRANGE(c1)SUBPARTITIONBYKEY(c2,c3)SUBPARTITIONS5(PARTITIONp0VALUESLESS THAN(0),PARTITIONp1VALU...
题目使用下列SQL语句创建教师表: CREATE TABLE 教师表(教师编号 I PRIMARY KEY,; 姓名 C(8) NOT NULL,; 职称 C(10) DEFAULT "讲师") 如果要删除“职称”字段的DEFAULT约束,正确的SQL语句是___。相关知识点: 试题来源: 解析 A 反馈 收藏
如果学生表STUDENT是使用下面的SQL语句创建的: Create table student(SNO C(4)) PRIMARY KEY Not Null; S
{ <collation_name> | database_default } ] [ FILETABLE_PRIMARY_KEY_CONSTRAINT_NAME = <constraint_name> ] [ FILETABLE_STREAMID_UNIQUE_CONSTRAINT_NAME = <constraint_name> ] [ FILETABLE_FULLPATH_UNIQUE_CONSTRAINT_NAME = <constraint_name> ] [ SYSTEM_VERSIONING = ON [ ( HISTORY_TABLE = ...
阅读下面SQL代码: CREATE TABLE student( id INT(3) PRIMARY KEY AUTO_INCREMENT, name VARCHAR(20) NOT NULL, grade FLOAT, ); 下面选项中,用于查询表中所有记录信息的SQL语句是相关知识点: 试题来源: 解析 SELECT id,name,grade FROM student;SELECT * FROM student; ...