Database

This contains some guidance on setting up a database for ICAT and which to choose.
The database system must be supported by eclipselink and must support transactions and enforce foreign key constraints. This includes most database systems you are likely to want as explained at the eclipselink web site It has been tested with: MySQL, Oracle and Derby.

You will need a schema/database with permissions for data definition operations such as “CREATE TABLE …” and for data manipulation operation such as “INSERT INTO …”.

Installation of those ICAT components that require a database will attempt to create the tables in the schema, but the schema itself must exist.

If you are using Glassfish You must place a copy of the “JDBC Connector” for your database in the lib/ext directory below the domain where you will install ICAT. You should get the connector from the database supplier. In the case of Oracle and MySQL these may be both included in the Glassfish distribution but must be copied to the lib directory. For Derby no action is required – the connector is pre-installed.

MySQL

MySQL must be installed with InnoDB support and you must ensure that while installing ICAT the default engine is InnoDB. You can see the default engine by entering  show engines; at the mysql command prompt.  To change the default on Linux add the line

default-storage-engine=innodb

to the [mysqld] section of /etc/my.cnf and restart mysqld.

To fix an existing system you can use the ALTER TABLE command as explained in: http://dev.mysql.com/doc/refman/5.1/en/storage-engine-setting.html. Don’t forget to run mysql_secure_installation if your package manager has not prompted you for a root password for the MySQL server.

On more recent versions of MySQL/MariaDB the default character set has been changed which results in some keys being too long and so tables do not get created. To avoid this problem always specify the default character set as utf8 when creating a database. For example:

create database icat DEFAULT CHARACTER SET utf8;

Oracle

Applications must be aware that Oracle does not treat empty strings correctly but stores them as NULL values. If you want your code to work on Oracle and other databases you must code round this issue.

To work properly with an RAC installation some options need setting in Glassfish. These will be set in future for updated components by the setup scripts. For now, for each Oracle JDBC connection pool set the following advanced properties:

  • Validate At Most Once: 60
  • Creation Retry Attempts: 10
  • Connection Validation: Required
  • Table Name: dual

Derby

Derby is not recommended for production use. There is much less experience of it.