mysql create table unique key
SQL UNIQUE Constraint on ALTER TABLE. To create a UNIQUE constraint on the "ID" column when the table is already created, use the following SQL: MySQL ... , 比如create table t(id int, unique indexinx_tx_id (id));--index當作了key使用 （2）最重要的也就是，不管如何描述，需要理解index是純粹 ... , 一、key與primary key區別. CREATE TABLE wh_logrecord ( logrecord_id int(11) NOT NULL auto_increment, user_name varchar(100) default ... , UNIQUE 唯一限制(SQL UNIQUE Constraint) ... CREATE TABLE customer ( C_Id INT NOT NULL UNIQUE, Name VARCHAR(50) NOT NULL, Address ... MySQL. ALTER TABLE customer DROP INDEX u_Customer_Id;. ,The following statement illustrates how to create a unique constraint when you create a table. CREATE TABLE table_name( ... UNIQUE KEY(index_column_, ... ,CREATE TABLE table_name( ..., column_name data_type UNIQUE, ... ); In this syntax, you include the UNIQUE keyword in the definition of the column that you ... ,A primary key must contain unique values. If the primary key ... Typically, you define the primary key for a table in the CREATE TABLE statement. If the primary ... ,In other words, every unique key on the table must use every column in the table's ... CREATE TABLE t1 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, ... mysql> CREATE TABLE t_no_pk (c1 INT, c2 INT) -> PARTITION BY ... ,A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an ... ,The syntax for creating a unique constraint using an ALTER TABLE statement in MySQL is: ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column1, column2, ... column_n);
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 mysql create table unique key 相關參考資料
SQL UNIQUE Constraint - W3Schools
SQL UNIQUE Constraint on ALTER TABLE. To create a UNIQUE constraint on the "ID" column when the table is already created, use the following SQL: MySQL ... https://www.w3schools.com Mysql中key 、primary key 、unique key 與index區別- IT閱讀
比如create table t(id int, unique indexinx_tx_id (id));--index當作了key使用 （2）最重要的也就是，不管如何描述，需要理解index是純粹 ... https://www.itread01.com mysql 建立、刪除索引key 、primary key 、unique key 與index ...
一、key與primary key區別. CREATE TABLE wh_logrecord ( logrecord_id int(11) NOT NULL auto_increment, user_name varchar(100) default ... https://www.itread01.com SQL UNIQUE Constraint 限制- SQL 語法教學Tutorial
UNIQUE 唯一限制(SQL UNIQUE Constraint) ... CREATE TABLE customer ( C_Id INT NOT NULL UNIQUE, Name VARCHAR(50) NOT NULL, Address ... MySQL. ALTER TABLE customer DROP INDEX u_Customer_Id;. https://www.fooish.com Using MySQL UNIQUE Index To Prevent Duplicates
The following statement illustrates how to create a unique constraint when you create a table. CREATE TABLE table_name( ... UNIQUE KEY(index_column_, ... https://www.mysqltutorial.org MySQL UNIQUE Constraint - MySQL Tutorial
CREATE TABLE table_name( ..., column_name data_type UNIQUE, ... ); In this syntax, you include the UNIQUE keyword in the definition of the column that you ... https://www.mysqltutorial.org MySQL Primary Key - MySQL Tutorial
A primary key must contain unique values. If the primary key ... Typically, you define the primary key for a table in the CREATE TABLE statement. If the primary ... https://www.mysqltutorial.org 23.6.1 Partitioning Keys, Primary Keys, and Unique Keys
In other words, every unique key on the table must use every column in the table's ... CREATE TABLE t1 ( col1 INT NOT NULL, col2 DATE NOT NULL, col3 INT NOT NULL, ... mysql> CREATE TABLE t_no_p... https://dev.mysql.com 13.1.20 CREATE TABLE Statement - MySQL :: Developer Zone
A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an ... https://dev.mysql.com MySQL: Unique Constraints - TechOnTheNet
The syntax for creating a unique constraint using an ALTER TABLE statement in MySQL is: ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column1, column2, ... column_n); https://www.techonthenet.com |