Write a SQL query to create a table with three columns: id, name, and age. Add a primary key constraint on the id column. Write a SQL query to create a table with four columns: product_id, product_name, price, and quantity. Ensure that the price column cannot have negative values...
MySQL常见的建表约束(Create Table Constraints) 一、MySQL约束类型 约束名称 描述 NOT NULL 非空约束 UNIQUE 唯一约束,取值不允许重复, PRIMARY KEY 主键约束(主关键字),自带非空、唯一、索引 FOREIGN KEY 外键约束(外关键字)
It has a "constraint_specification" for the Create table statement for primary_keyt etc. I tried but couldn't find the "constraint_specification" in Cloudera site for Hive. My questions are 1. Is it possible to create a Hive table with Not Null constraints? If yes, can you please provid...
] referenced_table_name [ ( ref_column ) ] | CHECK ( logical_expression ) } <table_constraint> ::= [ CONSTRAINT constraint_name ] { { PRIMARY KEY | UNIQUE } { NONCLUSTERED ( column_name [ ASC | DESC ] [ ,... n ]) | NONCLUSTERED HASH ( column_name [ ,... n ] ) WITH ...
可以在创建表时规定约束(通过 CREATE TABLE 语句),或者在表创建之后也可以(通过 ALTER TABLE 语句)。 我们将主要探讨以下几种约束: NOT NULL UNIQUE PRIMARY KEY FOREIGN KEY CHECK DEFAULT SQL NOT NULL 约束 NOT NULL 约束强制列不接受 NULL 值。
当一个类型化的表被创建时,列的数据类型由底层的组合类型决定而没有在CREATE TABLE命令中直接指定。但是CREATE TABLE命令可以对表增加默认值和约束,并且可以指定存储参数。 column_name列的名称会在新表中被建立. data_type列的数据类型. 这可以包括数组规格。 COLLATE collation COLLATE子句为该列(必须是一种可排序...
] referenced_table_name [ ( ref_column ) ] | CHECK ( logical_expression ) } <table_constraint> ::= [ CONSTRAINT constraint_name ] { { PRIMARY KEY | UNIQUE } { NONCLUSTERED ( column_name [ ASC | DESC ] [ ,... n ]) | NONCLUSTERED HASH ( column_name [ ,... n ] ) WITH ...
When creating a managed U-SQL table with a schema, a table schema has to be provided that contains at least one table column definition. Syntax Create_Managed_Table_With_Schema_Statement := 'CREATE' 'TABLE' ['IF' 'NOT' 'EXISTS']IdentifierTable_With_Schema. ...
CREATETABLECompanies (idintNOTNULLPRIMARYKEY,namevarchar(50), addresstext, emailvarchar(50), phonevarchar(10) ); To learn more, visitSQL PRIMARY KEY. Define constraints while creating a table We can also add different types of constraints while creating a table. For example, ...
WITH ( storage_parameter [= value ] [, ... ] ) | WITHOUT OIDS ] [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ] [ TABLESPACE tablespace_name ] CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name PARTITION OF parent_table ...