Change Alfresco Database Connection (Alfresco 3.3 or higher)

New updated version of the Alfresco comes with PostgreSQL. If you are still using Database other than PostgreSQL, you can change the Database following given steps:

1. Create a new "alfresco" database (Here i am assuming your current database is "alfresco")
2. Create a new 'alfresco' user. Set this user's password to 'alfresco'. (Here i am assuming your current user name and password are "alfresco")
3. Ensure that the alfresco user has the required privileges to create and modify tables.
4. Verify/modify the Alfresco data location in the alfresco-global.properties file.
5. Override some properties in alfresco-global.properties 
6. Start the application server (eg. Tomcat) to verify your configuration changes. 

If you are using MySQL you can follow these step:

1. Create a new "alfresco" database,here.

   CREATE DATABASE <DATABASENAME>;

2.  Create a new 'alfresco' user. Set this user's password to 'alfresco'.

   GRANT ALL PRIVILEGES ON alfresco.* To  

   'alfresco'@'localhost' IDENTIFIED BY 'alfresco';

3. Ensure that the alfresco user has the required privileges to create and modify tables 
4. Verify/modify the Alfresco data location in the alfresco-global.properties file. 
5. Override some properties in alfresco-global.properties
   

   db.name=alfresco
   db.username=alfresco
   db.password=alfresco
   db.host=localhost
   db.port=3306
   db.driver=org.gjt.mm.mysql.Driver
   db.url=jdbc:mysql://${db.host}:${db.port}/${db.name}
   db.pool.validate.query=select 1

   To recover all index back. You have to override these properties.

   db.schema.update=true
   index.recovery.mode=FULL
   db.schema.update.lockRetryCount=24
   db.schema.update.lockRetryWaitSeconds=5

6. Start the application server (eg. Tomcat) to verify your configuration changes.  

PostgreSQL example 

The following properties needs to change:  

alfresco-global.properties:

db.name=alfresco
db.username=alfresco
db.password=alfresco
db.host=localhost
db.port=5432
db.driver=org.postgresql.Driver
db.url=jdbc:postgresql://${db.host}:${db.port}/${db.name}

Ensure that the postgresql.conf file (pg_hba.conf for postgres 8.1.3) (refer to PostgreSQL documentation for more info on this file) contains:

host    all    all    127.0.0.1/32    password

Oracle example 

The following properties needs to change:  

alfresco-global.properties:

db.name=alfresco
db.username=alfresco
db.password=alfresco
db.host=localhost
db.port=1521
db.driver=oracle.jdbc.OracleDriver
db.url=jdbc:oracle:thin:@${db.host}:${db.port}:<database sid>
db.pool.validate.query=select 1 from dual 

Microsoft SQL Server example

The following properties needs to change:  

alfresco-global.properties:

db.name=alfresco
db.username=alfresco
db.password=alfresco
db.host=localhost
db.port=1433
db.driver=net.sourceforge.jtds.jdbc.Driver
db.url=jdbc:jtds:sqlserver://${db.host}:${db.port}/${db.name}
db.txn.isolation=4096
db.pool.validate.query=select 1

DB2 example

The following properties needs to change:  

alfresco-global.properties:

db.name=alfresco
db.username=alfresco
db.password=alfresco
db.host=localhost
db.port=50000
db.driver=com.ibm.db2.jcc.DB2Driver
db.url=jdbc:db2://${db.host}:${db.port}/${db.name}

Tips:

• JDBC errors

  In case of any JDBC diver error you have to copy corresponding driver in the Tomcat lib folder.
  
  
  

• For eg.
          Copy Oracle JDBC driver JAR (ojdbc14.jar) into \tomcat\lib folder
          Path of the Lib folder: "C:\Alfresco_Home\tomcat\lib"
         

• URL DB format

  Another URL DB format would be this if the first example do not works

• db.url=jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS = (PROTOCOL = TCP)(HOST = {db.host})(PORT = ${db.port}))
  (CONNECT_DATA =(SERVER = DEDICATED)(SID = )))
         

For Mor Informaton: Database_Configuration

Source : http://wiki.alfresco.com/wiki/Database_Configuration