Recover MySQL database from data folder without ibdata1 from ibd files

My WAMP directory accidentally get deleted by another user. Only data folder in MySQLis available. And, in that only database-folders (folders in "\bin\mysql\mysql5.6.12\data\" with name of databases) are available. All files including "ibdata1" in root of "\bin\mysql\mysql5.6.12\data\" are also deleted.

The database folders contains files with below extensions only.

.frm, .ibd

and "db.opt" file.

How the databases can be recovered?

I already have tried to recover bdata1. But, unable to get it back. And, some database contains MYISAM also.

MyISAM

For a MyISAM table mydb.mytable, you should have three files

• \bin\mysql\mysql5.6.12\data\mydb\mytable.frm

• \bin\mysql\mysql5.6.12\data\mydb\mytable.MYD

• \bin\mysql\mysql5.6.12\data\mydb\mytable.MYI

They should already be accessible as a table since each file contains needed data, metadata, and index info. Collectively, they form the table. There are no external storage engine mecahnisms to access.

InnoDB

Take a look at this Pictorial Representation of InnoDB

The only thing that attaches ibdata1 to the .ibd files is the data dictionary.

Your mission, should you decide to accept it, is to create each table and swap in the .ibd

Before you do anything, make a full copy of "\bin\mysql\mysql5.6.12\data" to another

Here is a sample

Suppose you have a database mydb with the table mytable. This means

• You have the folder \bin\mysql\mysql5.6.12\data\mydb

• Inside that folder, you have

• mytable.frm

• mytable.ibd

You need the .frm. If you look at my post How can extract the table schema from just the .frm file?, you can download a MySQL utility that can generate the SQL needed to create the table.

You should now do the following

• Move mytable.ibd to \bin\mysql\mysql5.6.12\data

• Run the SQL to create the InnoDB table

• Login to mysql and run ALTER TABLE mydb.mytable DISCARD TABLESPACE; (This will delete \bin\mysql\mysql5.6.12\data\mydb\mytable.ibd)

• Copy \bin\mysql\mysql5.6.12\data\mytable.ibd into \bin\mysql\mysql5.6.12\data\mydb

• Login to mysql and run ALTER TABLE mydb.mytable IMPORT TABLESPACE; (This will register \bin\mysql\mysql5.6.12\data\mydb\mytable.ibd into the data dictionary)

After this, the table mydb.mytable should be fully accessible. You can test that accessibility by simply running:

SELECT * FROM mydb.mytable LIMIT 10;

Give it a Try !!!

DRINK (Data Recovery Incorporates Necessary Knowledge) Responsibly

StackExchange Database Administrators Q#57120, answer score: 22