I have one table with name tbl_groupmaster
created with SQL as shown below:
create table tbl_groupmaster (
tgm_groupid int(10) unsigned NOT NULL auto_increment,
tgm_groupname varchar(50),
tgm_groupdescription varchar(50),
PRIMARY KEY (tgm_groupid)
)
and I am creating one more table with name tbl_groupmanager
, using a foreign key relationship:
create table tbl_groupmanager (
tgmgr_groupmangerid int(10) NOT NULL,
tgm_groupid int(10),
UserNamesID int(10),
tgmgr_groupsize int(10),
tgmgr_groupassigned_date datetime,
tgmgr_grouplead_status enum ('active','inactive'),
PRIMARY KEY (tgmgr_groupmangerid),
FOREIGN KEY (tgm_开发者_如何学Pythongroupid) REFERENCES tbl_groupmaster(tgm_groupid)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
But I am getting this error:
SQL Error: Can't create table '.\student\tbl_groupmanager.frm' (errno: 150)..
What is this? I am unable to identify my mistake. Please help me to resolve this. Thanks in advance.
The type of the foreign key has to be the same as the referenced key. Change tgm_groupid on table tbl_groupmanager to int(10) unsigned and it will work.
Most probably, MyISAM
is default engine in your database and hence tbl_groupmaster
is MyISAM
.
MyISAM
does not support foreign keys.
Your foreign key is not the same datatype as the primary key it references. One is unsigned, one isn't.
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