Database Objects
An Oracle database can contain multiple data structures. Each structure should be outlined in the database design so that it can be created during the build stage of database development.
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Table: Stores data
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View: Subset of data from one or more tables
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Sequence: Numeric value generator
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Index: Improves the performance of some queries
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Synonym: Gives alternative names to objects
Oracle9i Table Structures
Tables can be created at any time, even while users are using the database.
You do not need to specify the size of any table. The size is ultimately defined by the amount of space allocated to the database as a whole. It is important, however, to estimate how much space a table will use over time.Table structure can be modified online.
Tables can have up to 1,000 columns and must conform to standard database object-naming conventions. Column definitions can be omitted when using the AS subquery clause. Tables are created without data unless a query is specified. Rows are usually added by using INSERT statements.