diff -r 4816d766a08a -r f345bda72bc4 Symbian3/PDK/Source/GUID-FCBEE38E-FA6D-5C09-8B17-F18EF3E2E826.dita --- a/Symbian3/PDK/Source/GUID-FCBEE38E-FA6D-5C09-8B17-F18EF3E2E826.dita Tue Mar 30 11:42:04 2010 +0100 +++ b/Symbian3/PDK/Source/GUID-FCBEE38E-FA6D-5C09-8B17-F18EF3E2E826.dita Tue Mar 30 11:56:28 2010 +0100 @@ -1,12 +1,37 @@ - - - - - -Columns, column sets and keys

A database contains a collection of tables. A table contains a set of rows. A row contains a set of columns. Every row in a table conforms to a structure described by the table's column set. Each column has attributes such as a name, a type, a maximum length, etc. Column types include every type of integer, real, date-time and text supported by Symbian OS. In addition, a long binary column (sometimes known as BLOBs) may be written using the stream interface, allowing stream-aware components to use a database column for persistence.

Auto-increment columns support automatic key or id generation. Column names within a single table must be unique, and follow the rules for DBMS names. A column definition is encapsulated by the TDbCol class, and the set of columns which describes the table in the CDbColSet class.

Every index in a database is defined by its key, represented by the CDbKey class. Tables can index certain columns to sort their rows into a particular order, or provide fast key-based access to their rows. A key has attributes such as being unique or primary, a comparison specification for text columns, and a list of columns which make up the key, the TDbKeyCol class.

See also:

\ No newline at end of file + + + + + +Columns, +column sets and keysExplains the concepts of columns, column sets and keys. +

A database contains a collection of tables. A table +contains a set of rows. A row contains a set of columns. +Every row in a table conforms to a structure described by the table's column +set. Each column has attributes such as a name, a type, a maximum +length, etc. Column types include every type of integer, real, date-time and +text supported by the Symbian platform. In addition, a long binary +column (sometimes known as BLOBs) may be written using the stream interface, +allowing stream-aware components to use a database column for persistence.

+

Auto-increment columns support automatic key or id generation. Column names +within a single table must be unique, and follow the rules for DBMS names. +A column definition is encapsulated by the TDbCol class, +and the set of columns which describes the table in the CDbColSet class.

+

Every index in a database is defined by its key, +represented by the CDbKey class. Tables can index certain +columns to sort their rows into a particular order, or provide fast key-based +access to their rows. A key has attributes such as being unique or primary, +a comparison specification for text columns, and a list of columns which make +up the key, the TDbKeyCol class.

+

See also:

+ +
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