This is a topic that overall you never should have to do... Why? Because you created backups right... You have tested and know the backups work so you can just restore those backups and get your lost schema and related data...
However that one instance in the corner office.. you never got around to setting up.. it not that important... just crashed and now you realize how you actually do use it...
All is not lost..
MySQL released their MySQL utilities awhile back and since been replaced more with the MySQL Shell.
mysqlfrm is still very handy though when needing to pull out the schema from an FRM file in a quick and simple command and it is a simple install.
mysqlfrm --diagnostic city.frm
# WARNING: Cannot generate character set or collation names without the --server option.
# CAUTION: The diagnostic mode is a best-effort parse of the .frm file. As such, it may not identify all of the components of the table correctly. This is especially true for damaged files. It will also not read the default values for the columns and the resulting statement may not be syntactically correct.
# Reading .frm file for city.frm:
# The .frm file is a TABLE.
# CREATE TABLE Statement:
CREATE TABLE `city` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`Name` char(160) DEFAULT NULL,
`CountryCode` char(12) NOT NULL,
`District` char(80) NOT NULL,
`Population` int(11) NOT NULL,
PRIMARY KEY `PRIMARY` (`ID`),
KEY `CountryCode` (`CountryCode`),
KEY `popkey` (`Population`)
) ENGINE=InnoDB;
#...done.
So now that you have the schema you lost... rebuild the DB or table. For the sake of the example, I will say we just lost the city data from the world DB.
$ cp city.ibd /tmp/
$ cp city.ibd /tmp/
mysql> LOCK TABLES city WRITE;
mysql> ALTER TABLE city DISCARD TABLESPACE;
cp city.ibd /edb/local/mysql/data/rundeck/
chown tmdba:dba /edb/local/mysql/data/rundeck/city.ibd
mysql> ALTER TABLE city IMPORT TABLESPACE;
mysql> UNLOCK TABLES;
mysql> SELECT COUNT(*) FROM city;
