TDbKeyCol Class Reference
Detailed Description
Defines a key column in an index.
The data members are public as this is really a structure to group the attributes of the key column together. Two non-default constructors are provided for convenience.
Member Attribute Documentation
iLength
The maximum number of characters used to index Text or LongText columns. If equal to KDbUndefinedLength (the default), all the characters in the defined column will be used.
iName
The column name for the key.
Member Enumeration Documentation
Enum TOrder
Specifies whether a key column in an index should be sorted in ascending or descending order.
| Enumerator | Value | Description |
|---|
| EAsc | |
Use ascending order.
|
| EDesc | |
Use descending order.
|
Constructor & Destructor Documentation
TDbKeyCol ( )
Constructs an uninitialised object. Default constructor. It is necessary because there are also non-default constructors in this class.
TDbKeyCol ( const TDbKeyCol & )
| Parameter | Description | | This TDbKeyCol object will be constructed as an exact copy of aSrcKeyCol object. |
TDbKeyCol ( const TDesC &, TOrder )
| IMPORT_C | TDbKeyCol | ( | const TDesC & | aName, |
| | TOrder | anOrder = EAsc |
| | ) | |
TDbKeyCol ( const TDesC &, TInt, TOrder )
Constructs an object with the given name, ordering and optional truncation length.
| Parameter | Description | | aName | The column name. |
| aLength | If present, this specifies a limit on how many characters of a Text or LongText column are used for the key. This should only be used for the last key column in an index. It is required for keys on LongText columns. |
| anOrder | The ordering for the key column. By default this is ascending order. |
Member Function Documentation
operator= ( const TDbKeyCol & )
| Parameter | Description | | This TDbKeyCol object will be made to be an exact copy of aSrcKeyCol object. |