In a multi-database system, the usage of databases can vary a lot. Therefore you must consider the way that databases in your system will be used when physically implementing and tuning the databases.

The following guidelines are for using schemas and catalogs. See the section that applies to your Advanced Replication architecture.

A two-tier data redundancy model has one master database and multiple replica databases. It is recommended that you use identical schema names for the master and replica databases. Although you can use different schema names, be aware that different schema names in master and replica databases might complicate the application programming.

If you do not define a schema, the default schema name (user ID of the database owner) is used. However, if you want to create a non-default schema, you must do this before creating the database objects that are associated with the schema. To create a schema use the CREATE SCHEMA statement, see CREATE SCHEMA.

A multi-tier topology contains three or more tiers in the hierarchy of synchronized databases. The top tier of the topology is the master database for the overall system. The mid-tier databases of the topology have a dual role of both master and replica databases. The lowest tier contains only replica databases.

A multi-tier topology is especially useful in systems that have a wide geographic distribution and a potentially large number of replica databases that also have local data (data that does not require synchronization with the top-tier master). The data in this type of system is typically partitioned to limit data access to specific replica databases. For example, a network management system that contains a database to manage configuration and event information for a large managed network meets the criteria for a multi-tier topology.

A solidDB physical database file might contain more than one logical database. Each logical database is a complete, independent group of database objects, such as tables, indexes, procedures, triggers, and so on. Each logical database is implemented as a database catalog. Each of these catalogs can act as an independent master or replica database. This makes it possible, for example, to create two or more independent replica databases in one physical local database.

Multi-master topologies are useful in environments where a solidDB database is used by multiple applications. For example, a local database might contain a replica database of two master databases: one for a configuration management application and another one for a usage-monitoring application. Note that you can combine multi-tier and multi-master topologies.