This section describes some Oracle specific terms and concepts mentioned in the documentation of the eZ Publish Extension for Oracle® Database. Refer to the official documentation of Oracle for more information.

Note: Be aware of all the differences before migrating to Oracle, since it has several conceptual differences when comparing it to other database management systems like MySQL or PL/pgSQL. For example, in most part of DBMS consider a given number of characters (eg. 255) for field size limits. In Oracle a size in bytes is used instead. In oracle if you set a field's limit to 255 it will be size for the content in bytes, not the number or characters, since lots of characters can use more than 1 byte.

An Oracle database is a collection of specific files (control files, redo log files, data files, undo files and temp files). Every running Oracle database is associated with an Oracle instance. When a database is started on a database server, Oracle allocates a memory area (SGA) and starts one or more background processes (SMON, PMON and others). This combination of processes and shared memory is called an Oracle instance. An instance only exists when it is running. A database is normally managed by one and only one instance, unless the Oracle Real Application Clusters (RAC) technology is used.

You can also look at an Oracle database as a service that stores and retrieves data for clients. In a single instance environment (non-RAC), the words "service" and "instance" are often used as synonyms; the target instance to connect to is identified by a database service name.

In order to connect to an Oracle instance, a client needs a connect descriptor, which is a specially formatted description of the destination for a network connection. In most cases, such a descriptor specifies the protocol, host, port and service name that should be used. It is possible to define simple names that map to connect descriptors. For example, these can be defined in a "tnsnames.ora" file stored on a client. Users initiate a connect request by passing a username and password along with a simple name using the following format:

username/password@simple_name

In the latest versions of Oracle, the easy connect naming method can be used. It allows a client to connect to a database server with a connect string for a simple TCP/IP address, consisting of a host name and optional port and service name:

username/password@[//]host[:port][/service_name]

Note that the easy connect naming method is currently not supported by the database extension. Support for this feature will be added in the future (refer to this page for more information).

A schema is a named collection of objects (tables, indexes, procedures, etc.) associated with a user account. The word "schema" can also be used to refer to an Oracle account. Oracle database installations usually come with a default schema that can be accessed using "scott" as the username and "tiger" as the password.

An Oracle database is divided into one or more logical storage units called tablespaces. Tables and indexes are created within a particular tablespace. The primary tablespace in any database is the SYSTEM tablespace, which Oracle creates automatically when the database is created. This tablespace is always online when the database is open. You can assign each user a tablespace quota in order to limit the amount of space allocated for storage of the user's objects within the specified tablespace. By default, a user has no quota on any tablespace in the database. If the user has the privilege to create a schema object, you must assign a quota to allow the user to create objects.

SQL*Plus is an Oracle command line tool for running SQL and PL/SQL commands. This utility is often used by database administrators and developers to interact with the Oracle database. You can interact with SQL*Plus directly through the command line or through scripts. Refer to the documentation of SQL*Plus for more information.