Hi,
my environment is as follow:
this is my create table statement
this is what I get from show create table
as you realize the name of the primary key constraint is not effective.
why is this so? from MySQL :: MySQL 5.5 Reference Manual :: 13.1.17 CREATE TABLE Syntax, I doubt that there's anything wrong with my syntax.
also there's another issue:
if you take a close look, you will realize that index type is BTREE and not HASH as desired. why is this so, is there something wrong with my syntax?
thanks for any guidance!
my environment is as follow:
Code:
mysql> show variables where variable_name like '%version%';
+-------------------------+------------------------------+
| Variable_name | Value |
+-------------------------+------------------------------+
| innodb_version | 1.1.8 |
| protocol_version | 10 |
| slave_type_conversions | |
| version | 5.5.27 |
| version_comment | MySQL Community Server (GPL) |
| version_compile_machine | x86 |
| version_compile_os | Win32 |
+-------------------------+------------------------------+
7 rows in set (0.00 sec)Code:
create table if not exists test1(
test1_id int,
test1_string varchar(10),
constraint pk_test1 primary key (test1_id) using hash comment 'primary key index for test1'
);Code:
mysql> show create table test1;
+-------+-----------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------+
| Table | Create Table
|
+-------+-----------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------+
| test1 | CREATE TABLE `test1` (
`test1_id` int(11) NOT NULL DEFAULT '0',
`test1_string` varchar(10) DEFAULT NULL,
PRIMARY KEY (`test1_id`) USING HASH COMMENT 'primary key index for test1'
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |Code:
mysql> select CONSTRAINT_SCHEMA, CONSTRAINT_NAME, TABLE_SCHEMA, CONSTRAINT_TYPE
from INFORMATION_SCHEMA.TABLE_CONSTRAINTS where TABLE_NAME='test1';
+-------------------+-----------------+--------------+-----------------+
| CONSTRAINT_SCHEMA | CONSTRAINT_NAME | TABLE_SCHEMA | CONSTRAINT_TYPE |
+-------------------+-----------------+--------------+-----------------+
| certify | PRIMARY | certify | PRIMARY KEY |
+-------------------+-----------------+--------------+-----------------+
1 row in set (0.02 sec)also there's another issue:
Code:
mysql> show index from test1;
+-------+------------+----------+--------------+-------------+-----------+------
-------+----------+--------+------+------------+---------+----------------------
-------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardi
nality | Sub_part | Packed | Null | Index_type | Comment | Index_comment
|
+-------+------------+----------+--------------+-------------+-----------+------
-------+----------+--------+------+------------+---------+----------------------
-------+
| test1 | 0 | PRIMARY | 1 | test1_id | A |
0 | NULL | NULL | | BTREE | | primary key index for
test1 |
+-------+------------+----------+--------------+-------------+-----------+------
-------+----------+--------+------+------------+---------+----------------------
-------+
1 row in set (0.00 sec)if you take a close look, you will realize that index type is BTREE and not HASH as desired. why is this so, is there something wrong with my syntax?
thanks for any guidance!