How do I quickly rename a MySQL database (change schema name)? ~ Tech Blog

Tuesday, 30 October 2018

How do I quickly rename a MySQL database (change schema name)?

The MySQL manual at MySQL covers this.

Usually I just dump the database and reimport it with a new name. This is not an option for very big databases. Apparently RENAME {DATABASE | SCHEMA} db_name TO new_db_name; does bad things, exist only in a handful of versions, and is a bad idea overall.

This needs to work with InnoDB, which stores things very differently than MyISAM.

Answers

For InnoDB, the following seems to work: create the new empty database, then rename each table in turn into the new database:

RENAME TABLE old_db.table TO new_db.table;

You will need to adjust the permissions after that.

For scripting in a shell, you can use either of the following:

mysql -u username -ppassword old_db -sNe 'show tables' | while read table; \ 
    do mysql -u username -ppassword -sNe "rename table old_db.$table to new_db.$table"; done

for table in `mysql -u root -ppassword -s -N -e "use old_db;show tables from old_db;"`; do mysql -u root -ppassword -s -N -e "use old_db;rename table old_db.$table to new_db.$table;"; done;

Notes: there is no space between the option -p and the password. If your database has no password, remove the -u username -ppassword part.

Also, if you have stored procedures, you can copy them afterwards:

mysqldump -R old_db | mysql new_db

I think the solution is simpler and was suggested by some developers. phpMyAdmin has an operation for this.

From phpMyAdmin, select the database you want to select. In the tabs there's one called Operations, go to the rename section. That's all.

It does, as many suggested, create a new database with the new name, dump all tables of the old database into the new database and drop the old database.

Three options:

Create the new database, bring down the server, move the files from one database folder to the other, and restart the server. Note that this will only work if ALL of your tables are MyISAM.
Create the new database, use CREATE TABLE ... LIKE statements, and then use INSERT ... SELECT * FROM statements.
Use mysqldump and reload with that file.

I've only recently came across a very nice way to do it, works with MyISAM and InnoDB and is very fast:

RENAME TABLE old_db.table TO new_db.table;

I don't remember where I read it but credit goes to someone else not me.

This is what I use:

$ mysqldump -u root -p olddb >~/olddb.sql
$ mysql -u root -p
mysql> create database newdb;
mysql> use newdb
mysql> source ~/olddb.sql
mysql> drop database olddb;

Simplest bullet-and-fool-proof way of doing a complete rename (including dropping the old database at the end so it's a rename rather than a copy):

mysqladmin -uroot -pmypassword create newdbname
mysqldump -uroot -pmypassword --routines olddbname | mysql -uroot -pmypassword newdbname
mysqladmin -uroot -pmypassword drop olddbname

Steps:

Copy the lines into Notepad.
Replace all references to "olddbname", "newdbname", "mypassword" (+ optionally "root") with your equivalents.
Execute one by one on the command line (entering "y" when prompted).

For those who are Mac users, Sequel Pro has a Rename Database option in the Database menu. http://www.sequelpro.com/

You may use this shell script:

Reference: How to rename a MySQL database?

#!/bin/bash
set -e # terminate execution on command failure

mysqlconn="mysql -u root -proot"
olddb=$1
newdb=$2
$mysqlconn -e "CREATE DATABASE $newdb"
params=$($mysqlconn -N -e "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES \
                           WHERE table_schema='$olddb'")
for name in $params; do
      $mysqlconn -e "RENAME TABLE $olddb.$name to $newdb.$name";
done;
$mysqlconn -e "DROP DATABASE $olddb"

It's working:

$ sh rename_database.sh oldname newname

Here is a batch file I wrote to automate it from the command line, but it for Windows/MS-DOS.

Syntax is rename_mysqldb database newdatabase -u [user] -p[password]

:: ***************************************************************************
:: FILE: RENAME_MYSQLDB.BAT
:: ***************************************************************************
:: DESCRIPTION
:: This is a Windows /MS-DOS batch file that automates renaming a MySQL database 
:: by using MySQLDump, MySQLAdmin, and MySQL to perform the required tasks.
:: The MySQL\bin folder needs to be in your environment path or the working directory.
::
:: WARNING: The script will delete the original database, but only if it successfully
:: created the new copy. However, read the disclaimer below before using.
::
:: DISCLAIMER
:: This script is provided without any express or implied warranties whatsoever.
:: The user must assume the risk of using the script.
::
:: You are free to use, modify, and distribute this script without exception.
:: ***************************************************************************

:INITIALIZE
@ECHO OFF
IF [%2]==[] GOTO HELP
IF [%3]==[] (SET RDB_ARGS=--user=root) ELSE (SET RDB_ARGS=%3 %4 %5 %6 %7 %8 %9)
SET RDB_OLDDB=%1
SET RDB_NEWDB=%2
SET RDB_DUMPFILE=%RDB_OLDDB%_dump.sql
GOTO START

:START
SET RDB_STEP=1
ECHO Dumping "%RDB_OLDDB%"...
mysqldump %RDB_ARGS% %RDB_OLDDB% > %RDB_DUMPFILE%
IF %ERRORLEVEL% NEQ 0 GOTO ERROR_ABORT
SET RDB_STEP=2
ECHO Creating database "%RDB_NEWDB%"...
mysqladmin %RDB_ARGS% create %RDB_NEWDB%
IF %ERRORLEVEL% NEQ 0 GOTO ERROR_ABORT
SET RDB_STEP=3
ECHO Loading dump into "%RDB_NEWDB%"...
mysql %RDB_ARGS% %RDB_NEWDB% < %RDB_DUMPFILE%
IF %ERRORLEVEL% NEQ 0 GOTO ERROR_ABORT
SET RDB_STEP=4
ECHO Dropping database "%RDB_OLDDB%"...
mysqladmin %RDB_ARGS% drop %RDB_OLDDB% --force
IF %ERRORLEVEL% NEQ 0 GOTO ERROR_ABORT
SET RDB_STEP=5
ECHO Deleting dump...
DEL %RDB_DUMPFILE%
IF %ERRORLEVEL% NEQ 0 GOTO ERROR_ABORT
ECHO Renamed database "%RDB_OLDDB%" to "%RDB_NEWDB%".
GOTO END

:ERROR_ABORT
IF %RDB_STEP% GEQ 3 mysqladmin %RDB_ARGS% drop %NEWDB% --force
IF %RDB_STEP% GEQ 1 IF EXIST %RDB_DUMPFILE% DEL %RDB_DUMPFILE%
ECHO Unable to rename database "%RDB_OLDDB%" to "%RDB_NEWDB%".
GOTO END

:HELP
ECHO Renames a MySQL database.
ECHO Usage: %0 database new_database [OPTIONS]
ECHO Options: Any valid options shared by MySQL, MySQLAdmin and MySQLDump.
ECHO          --user=root is used if no options are specified.
GOTO END    

:END
SET RDB_OLDDB=
SET RDB_NEWDB=
SET RDB_ARGS=
SET RDB_DUMP=
SET RDB_STEP=

I potsed a question on Server Fault trying to get around downtime when restoring very large databases by using MySQL Proxy. I didn't have any success, but I realized in the end what I wanted was RENAME DATABASE functionality because dump/import wasn't an option due to the size of our database.

There is a RENAME TABLE functionality built in to MySQL so I ended up writing a simple Python script to do the job for me. I've posted it on GitHub in case it could be of use to others.

The simplest method is to use HeidiSQL software. It's free and open source. It runs on Windows and on any Linux with Wine (run Windows applications on Linux, BSD, Solaris and Mac OS X).

To download HeidiSQL, goto http://www.heidisql.com/download.php.

To download Wine, goto http://www.winehq.org/.

To rename a database in HeidiSQL, just right click on the database name and select 'Edit'. Then enter a new name and press 'OK'.

It is so simple.

Here is a quick way to generate renaming sql script, if you have many tables to move.

SELECT DISTINCT CONCAT('RENAME TABLE ', t.table_schema,'.', t.table_name, ' TO ',     
t.table_schema, "_archive", '.', t.table_name, ';' ) as Rename_SQL 
FROM information_schema.tables t
WHERE table_schema='your_db_name' ;

If you are using phpMyAdmin you can go to the "operations" tab once you have selected the database you want to rename. Then go to the last section "copy database to" (or something like that), give a name, and select the options below. In this case, I guess you must select "structure and data" and "create database before copying" checkboxes and, finally, press the "go" button in that section.

By the way, I'm using phpMyAdmin in Spanish so I'm not sure what the names of the sections are in English.

Seems noone mentioned this but here is another way:

create database NewDatabaseName like OldDatabaseName;

then for each table do:

create NewDatabaseName.tablename like OldDatabaseName.tablename;
insert into NewDataBaseName.tablename select * from OldDatabaseName.tablename;

then, if you want to,

drop database OldDatabaseName;

This approach would have the advantage of doing the entire transfer on server with near zero network traffic, so it will go a lot faster than a dump/restore.

If you do have stored procedures/views/etc you might want to transfer them as well.

In MySQL Administrator do the following:

Under Catalogs, create a new database schema.
Go to Backup and create a backup of the old schema.
Execute backup.
Go to Restore and open the file created in step 3.
Select 'Another Schema' under Target Schema and select the new database schema.
Start Restore.
Verify new schema and, if it looks good, delete the old one.

Tech Blog

Tuesday, 30 October 2018