(I'd like to know if I should be dropping and recreating the indexes, too, or if MySQL will do what I'm hoping. I looked through the MySQL reference guide for ALTER TABLE, and I found mention that if the size of a column is decreased to less than an index's length then the index will be shortened, but I couldn't find anything indicating what would happen to an index if the underlying column grows in size. But my question is, does MySQL update this key to be applicable for BIGINTs, or does it maintain only INT capabilities? Now, I've noticed that when doing these modifications, the key FK1 is still present after the constraint is dropped, and I assume it's still applicable after the constraint is recreated. MODIFY ID BIGINT(20) NOT NULL AUTO_INCREMENT,ĪLTER TABLE FactTable MODIFY ID BIGINT(20) NOT NULL AUTO_INCREMENT ĪLTER TABLE AttemptTable ADD CONSTRAINT FK1 FOREIGN KEY (FactID) So the course of my updates has been: ALTER TABLE AttemptTable DROP FOREIGN KEY FK1, Change datatype of a column without losing data: MODIFY. Where AttemptTable has KEY FK1 (FactID) and CONSTRAINT FK1 FOREIGN KEY (FactID) REFERENCES FactTable (ID). This article will see how to change or modify the datatype of a column in MySQL. | ID | int(11) | NO | PRI | NULL | auto_increment | You need to use the ALTER TABLE / ALTER COLUMN feature. | Field | Type | Null | Key | Default | Extra | I'm using MySQL version 5.0.82 with InnoDB tables.

How to change column type in mySQL from DATE to DATETIME. How to change a columns datatype from text to datetime in mysql 0. MySQL: Changing column type and date time format. I'm in the process of updating my AUTO_INCREMENT PRIMARY KEY ID columns from INT to BIGINT. MySQL alter table and convert data from text to datetime.

Mysql alter column type