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For example, a heavily used index can be placed on a fast SSD. On the other hand, a database table which contains archived data that is rarely accessed could be stored on a less expensive but slower magnetic hard drive. While it is common for tablespaces to store their data in a filesystem file, a single file must be part of a single tablespace.
However, Oracle databases store schema objects logically within a tablespace of the database. The data of each object is physically contained in one or more of the tablespace's datafiles . For some objects (such as tables, indexes, and clusters) a database administrator can specify how much disk space the Oracle RDBMS allocates for the object ...
Application- or user-specific database objects in relational databases are usually created with data definition language (DDL) commands, which in SQL for example can be CREATE, ALTER and DROP. [4] [5] Rows or tuples from the database can represent objects in the sense of object-oriented programming, but are not considered database objects. [6]
Oracle has its own spin where creating a user is synonymous with creating a schema. Thus a database administrator can create a user called PROJECT and then create a table PROJECT.TABLE. Users can exist without schema objects, but an object is always associated with an owner (though that owner may not have privileges to connect to the database).
SQLite: A VIEW named "dual" that works the same as the Oracle "dual" table can be created as follows: CREATE VIEW dual AS SELECT 'x' AS dummy; SAP HANA has a table called DUMMY that works the same as the Oracle "dual" table. Teradata database does not require a dummy table. Queries like 'select 1 + 1' can be run without a "from" clause/table name.
The names of tables and columns in many Oracle production databases in use today are due to the use of Oracle Designer. Later versions of the tool allowed specification of most of the internals of the Oracle database such as tablespaces and files. Database Definition Language (DDL) generation from the Database design. Function model.
Query by Example (QBE) is a database query language for relational databases. It was devised by Moshé M. Zloof at IBM Research during the mid-1970s, in parallel to the development of SQL . [ 1 ] It is the first graphical query language, using visual tables where the user would enter commands, example elements and conditions.
The Oracle version of Navicat supports most of the latest Oracle objects features including Directory, Tablespace, Synonym, Materialized View, Trigger, Sequence, and Type, etc. [9] [10] Navicat for SQLite was released for Windows and Mac OS X simultaneously in April 2009, and the Linux version soon followed two months later in June of the same ...