Compare structures of two databases?

Question

I wanted to ask whether it is possible to compare the complete database structure of two huge databases. We have two databases, the one is a development database, the other a p

Answer 1

For mysql on Linux, it is possible via phpmyadmin to export the databases without 'data' and only structure.

Scrolling through the export options for the entire database, just deselect 'data' and set the output to text. Export both databases you wish to compare.

Then in file compare in your preferred program / site, compare the two text file outputs of the databases. Synchronization is still manual in this solution, but this is effective for comparing and finding the structural differences.

Answer 2

To answer this kind of question currently, I've made a script that uses information_schema content to compare column, datatype, and table

SET @database_current = '<production>';
SET @database_dev = '<development>';
-- column and datatype comparison
SELECT a.TABLE_NAME, a.COLUMN_NAME, a.DATA_TYPE, a.CHARACTER_MAXIMUM_LENGTH,
    b.COLUMN_NAME, b.DATA_TYPE, b.CHARACTER_MAXIMUM_LENGTH
FROM information_schema.COLUMNS a
    LEFT JOIN information_schema.COLUMNS b ON b.COLUMN_NAME = a.COLUMN_NAME
        AND b.TABLE_NAME = a.TABLE_NAME
        AND b.TABLE_SCHEMA = @database_current
WHERE a.TABLE_SCHEMA = @database_dev
    AND (
        b.COLUMN_NAME IS NULL
        OR b.COLUMN_NAME != a.COLUMN_NAME
        OR b.DATA_TYPE != a.DATA_TYPE
        OR b.CHARACTER_MAXIMUM_LENGTH != a.CHARACTER_MAXIMUM_LENGTH
    );
-- table comparison    
SELECT a.TABLE_SCHEMA, a.TABLE_NAME, b.TABLE_NAME
FROM information_schema.TABLES a
    LEFT JOIN information_schema.TABLES b ON b.TABLE_NAME = a.TABLE_NAME
        AND b.TABLE_SCHEMA = @database_current
WHERE a.TABLE_SCHEMA = @database_dev
    AND (
        b.TABLE_NAME IS NULL
        OR b.TABLE_NAME != a.TABLE_NAME
    );

Hope this script can also help people that looks for a non-application solution, but the usage of script. Cheers

Answer 3

You can just dump them with --no-data and compare the files.

Remember to use the --lock-tables=0 option on your production database to avoid the big nasty global lock.

If you use the same mysqldump version (your dev and production systems should have the same software, right?) then you'll expect to get more-or-less identical files out. The tables will be in alpha order so a simple diff will show discrepancies up easily.

Answer 4

You'll need a tool, probably, like Database comparer.

Answer 5

You can use the command line:

mysqldump --skip-comments --skip-extended-insert -d --no-data -u root -p dbName1>file1.sql
mysqldump --skip-comments --skip-extended-insert -d --no-data -u root -p dbName2>file2.sql
diff file1.sql file2.sql