Mysql分区:分区键和唯一索引主键的关系

今天主要介绍下面这几个错误:

ERROR 1503 (HY000): A PRIMARY KEY must include all columns in the table's partitioning

ERROR 1503 (HY000): A UNIQUE INDEX must include all columns in the table's partitioning function

主键必须包括表的分区函数中的所有列，一个惟一的索引必须包括表的分区函数中的所有列，是不是不太好理解意思

其实就是这么个意思：表上的每一个唯一性索引必须用于分区表的表达式上（其中包括主键索引） 

下面我来举几个例子：

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,   
     PRIMARY KEY (id)  
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

[Err] 1503 - A PRIMARY KEY must include all columns in the table's partitioning function

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,    
     UNIQUE KEY (id)  
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

[Err] 1503 - A PRIMARY KEY must include all columns in the table's partitioning function

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,   
     PRIMARY KEY (id,bid)  
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

Query OK, 0 rows affected (0.535 sec)

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,    
     UNIQUE KEY (id,bid)  
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

Query OK, 0 rows affected (0.625 sec)

这一组例子说明了如果要用bid作为分区key，则bid至少要包含在主键或者唯一键。

再来看一组例子：

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,  
     PRIMARY KEY (id,aid),
     UNIQUE KEY (bid)    
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

[Err] 1503 - A PRIMARY KEY must include all columns in the table's partitioning function

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,  
     PRIMARY KEY (id,aid),
     UNIQUE KEY (bid)    
)  
PARTITION BY KEY(aid)  
PARTITIONS 10;

[Err] 1503 - A PRIMARY KEY must include all columns in the table's partitioning function

这2个分区表是无法建立的，因为没有一个分区键，可以同时属于两个唯一性索引的键。

下面再来看一组例子：

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,  
     PRIMARY KEY (id,aid,bid)   
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

Query OK, 0 rows affected (0.475 sec)

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,  
     UNIQUE KEY (id,aid,bid)   
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

Query OK, 0 rows affected (0.532 sec)

SQL

CREATE TABLE t1 (  
     id INT NOT NULL,  
     aid DATE NOT NULL,  
     bid INT NOT NULL,  
     PRIMARY KEY (id,aid,bid),
     UNIQUE KEY (bid)    
)  
PARTITION BY KEY(bid)  
PARTITIONS 10;

Query OK, 0 rows affected (0.526 sec)

这三个都建立分区表成功了，因为bid同时属于一个或以上的唯一性索引的键

通过上面这些例子，大家可以深入的理解Mysql分区中分区键和唯一索引主键的关系了，希望对大家有所帮助。