【笔记】开发指南—DDL语句—分库分表语法—CREATE INDEX

CREATE [UNIQUE]
    GLOBAL INDEX index_name [index_type]
    ON tbl_name (index_sharding_col_name,...)
    global_secondary_index_option
    [index_option]
    [algorithm_option | lock_option] ...
# 全局二级索引特有语法，具体说明请参见CREATE TABLE文档
global_secondary_index_option:
    [COVERING (col_name,...)]
    drds_partition_options
# 分库分表子句，具体说明请参见CREATE TABLE文档
drds_partition_options:
    DBPARTITION BY db_sharding_algorithm
    [TBPARTITION BY {table_sharding_algorithm} [TBPARTITIONS num]]
db_sharding_algorithm:
    HASH([col_name])
  | {YYYYMM|YYYYWEEK|YYYYDD|YYYYMM_OPT|YYYYWEEK_OPT|YYYYDD_OPT}(col_name)
  | UNI_HASH(col_name)
  | RIGHT_SHIFT(col_name, n)
  | RANGE_HASH(col_name, col_name, n)
table_sharding_algorithm:
    HASH(col_name)
  | {MM|DD|WEEK|MMDD|YYYYMM|YYYYWEEK|YYYYDD|YYYYMM_OPT|YYYYWEEK_OPT|YYYYDD_OPT}(col_name)
  | UNI_HASH(col_name)
  | RIGHT_SHIFT(col_name, n)
  | RANGE_HASH(col_name, col_name, n)
 # 以下为MySQL DDL语法
index_sharding_col_name:
    col_name [(length)] [ASC | DESC] # length参数仅用于在索引表拆分键上创建局部索引
index_option:
    KEY_BLOCK_SIZE [=] value
  | index_type
  | WITH PARSER parser_name
  | COMMENT 'string'
index_type:
    USING {BTREE | HASH}
algorithm_option:
    ALGORITHM [=] {DEFAULT|INPLACE|COPY}
lock_option:
    LOCK [=] {DEFAULT|NONE|SHARED|EXCLUSIVE}

# 创建表
CREATE TABLE t_order (
  `id` bigint(11) NOT NULL AUTO_INCREMENT,
  `order_id` varchar(20) DEFAULT NULL,
  `buyer_id` varchar(20) DEFAULT NULL,
  `seller_id` varchar(20) DEFAULT NULL,
  `order_snapshot` longtext DEFAULT NULL,
  `order_detail` longtext DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `l_i_order` (`order_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 dbpartition by hash(`order_id`);
# 创建全局二级索引
ALTER TABLE t_order ADD UNIQUE GLOBAL INDEX `g_i_buyer` (`buyer_id`) COVERING (`order_snapshot`) dbpartition by hash(`buyer_id`);

mysql> show index from t_order;  
+---------+------------+------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+----------+---------------+   
| TABLE   | NON_UNIQUE | KEY_NAME   | SEQ_IN_INDEX | COLUMN_NAME | COLLATION | CARDINALITY | SUB_PART | PACKED | NULL | INDEX_TYPE | COMMENT  | INDEX_COMMENT |    
+---------+------------+------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+----------+---------------+   
| t_order |          0 | PRIMARY    |            1 | id          | A         |           0 |     NULL | NULL   |      | BTREE      |          |               |  
| t_order |          1 | l_i_order  |            1 | order_id    | A         |           0 |     NULL | NULL   | YES  | BTREE      |          |               |   
| t_order |          1 | g_i_seller |            1 | seller_id   | NULL      |           0 |     NULL | NULL   | YES  | GLOBAL     | INDEX    |               | 
| t_order |          1 | g_i_seller |            2 | id          | NULL      |           0 |     NULL | NULL   |      | GLOBAL     | COVERING |               |   
| t_order |          1 | g_i_seller |            3 | order_id    | NULL      |           0 |     NULL | NULL   | YES  | GLOBAL     | COVERING |               |   
+---------+------------+------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+----------+---------------+

mysql> show global index from t_order;    
+---------------------+---------+------------+------------+-------------+----------------+------------+------------------+---------------------+--------------------+------------------+---------------------+--------------------+--------+    
| SCHEMA              | TABLE   | NON_UNIQUE | KEY_NAME   | INDEX_NAMES | COVERING_NAMES | INDEX_TYPE | DB_PARTITION_KEY | DB_PARTITION_POLICY | DB_PARTITION_COUNT | TB_PARTITION_KEY | TB_PARTITION_POLICY | TB_PARTITION_COUNT | STATUS |
+---------------------+---------+------------+------------+-------------+----------------+------------+------------------+---------------------+--------------------+------------------+---------------------+--------------------+--------+    
| ZZY3_DRDS_LOCAL_APP | t_order | 1          | g_i_seller | seller_id   | id, order_id   | NULL       | seller_id        | HASH                | 4                  |                  | NULL                | NULL               | PUBLIC |   
+---------------------+---------+------------+------------+-------------+----------------+------------+------------------+---------------------+--------------------+------------------+---------------------+--------------------+--------+

mysql> show create table g_i_seller;