AI代码解释 ---Table structureforgrade---DROPTABLEIFEXISTS`grade`;CREATETABLE`grade`(`id`int(11)NOTNULLAUTO_INCREMENTCOMMENT'id',`sno`varchar(20)CHARACTERSETutf8COLLATEutf8_unicode_ciNULLDEFAULTNULLCOMMENT'学号',`courseName`varchar(20)CHARACTERSETutf8COLLATEutf8_unicode_ciNULLDEFAULTNULLCOMMENT'课程...
To have a proper database, you need to follow constraints that will create a table with certain conditions of SQL constraints. The SQL constraint is a rule used to maintain accuracy and integrity. There are some types of constraints in SQL that can be used based on the types of ...
SQL UNIQUE Constraint on ALTER TABLE
SQL PRIMARY KEY Constraint on CREATE TABLE 下面的 SQL 在“Persons” 表创建时在 “Id_P” 列创建 PRIMARY KEY 约束: MySQL: CREATETABLEPersons(Id_PintNOTNULL,LastNamevarchar(255)NOTNULL,FirstNamevarchar(255),Addressvarchar(255),Cityvarchar(255),PRIMARYKEY(Id_P)) 1. 2. 3. 4. 5. 6. 7. ...
<table_constraint> ::= [ CONSTRAINT constraint_name ] { { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] ( column_name [ ASC | DESC ] [ ,... n ] ) [ WITH FILLFACTOR = fillfactor | WITH ( <index_option> [ ,... n ] ) ] [ ON { partition_scheme_name (partition_column...
( PAD_INDEX = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON ) ON [PRIMARY]; /*(3) Create constraints matching the partition that will be switched out*/ ALTER TABLE [dbo].[...
Create table 语法 Constraints 约束语法 Not null 约束用法 Unique 约束用法 Primary key约束语法 Foreign key 约束语法 Check 约束语法 Default 约束语法 Create index 语法 Auto increment 字段(MySQL)/ Identity字段(SqL Server) Create view 语法 NULL 值 三、函数 AVG()函数 COUNT()函数 FIRST()、LAST()函数...
Is a column or list of columns specified in parentheses that are used in a new constraint. [ASC| DESC ] Specifies the order in which the column or columns participating in table constraints are sorted. The default is ASC. WITH FILLFACTOR=fillfactor ...
You must also have space quota in the tablespace in which space is to be acquired in order to use the add_table_partition, modify_table_partition, move_table_partition, and split_table_partition clauses. Additional Prerequisites for Constraints and Triggers...
The table declaration includes column definitions, names, data types, and constraints. The only constraint types allowed are PRIMARY KEY, UNIQUE KEY, and NULL. For more information about the syntax, see CREATE TABLE (Transact-SQL), CREATE FUNCTION (Transact-SQL), and DECLARE @local_variable (...