mysql create table unique key
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 ...
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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 |