Class CDbKey

class CDbKey : public CBase;

Description

Represents the definition of an index. The key may be unique or primary, it can specify the sort of comparison which is made for Text columns, and it has a list of columns which make up the key. The class is used to construct and interrogate index keys.

This class is not intended for user derivation.

Derivation

• CBase - Base class for all classes to be instantiated on the heap.

• CDbKey - Represents the definition of an index. The key may be unique or primary, it can ...

Members

Defined in CDbKey:

• AddL(const TDbKeyCol &)Adds a key column to the end of the key.
• CDbKey()Constructs an empty key. It is initialised to non-unique, non-primary and normal...
• Clear()Resets the key to its initial empty state.
• Comparison()constReturns the method used to compare Text columns in this key.
• Count()const
• EPrimary
• EUnique
• IsPrimary()constTests whether the key is the primary key.
• IsUnique()constTests whether the key is unique.
• MakePrimary()
• MakeUnique()Makes the key unique. This ensures that every key value in the index is distinct...
• NewL()Constructs and returns a pointer to a new empty key.
• NewLC()Constructs and returns a new empty key and return a pointer to it, leaving a poi...
• Remove(const TDesC &)Removes the named column from the key.
• SetComparison(TDbTextComparison)Sets the way in which Text columns are compared for the key. All Text columns in...
• anonymous
• operator[](TInt)constReturns a key column by its position in the key.
• ~CDbKey()Frees resources owned by the object.

Inherited from CBase:

• Delete(CBase *)Deletes the specified object.
• Extension_(TUint,TAny *&,TAny *)Extension function
• operator new(TUint)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TAny *)Initialises the object to binary zeroes.
• operator new(TUint,TLeave)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TLeave,TUint)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TUint)Allocates the object from the heap and then initialises its contents to binary z...

IMPORT_C CDbKey();

Description

Constructs an empty key. It is initialised to non-unique, non-primary and normal text comparison.

IMPORT_C static CDbKey* NewL();

Description

Constructs and returns a pointer to a new empty key.

Return value

IMPORT_C static CDbKey* NewLC();

Description

Constructs and returns a new empty key and return a pointer to it, leaving a pointer to the key object on the cleanup stack. This allows the key object and allocated resources to be cleaned up if a subsequent leave occurs.

Return value

IMPORT_C ~CDbKey();

Description

Frees resources owned by the object.

IMPORT_C CDbKey& AddL(const TDbKeyCol &aKeyCol);

Description

Adds a key column to the end of the key.

Parameters

Return value

IMPORT_C void Remove(const TDesC &aColName);

Description

Removes the named column from the key.

Parameters

IMPORT_C void Clear();

Description

Resets the key to its initial empty state.

inline TInt Count() const;

Description

Return value

inline const TDbKeyCol& operator[](TInt aCol) const;

Description

Returns a key column by its position in the key.

Parameters

Return value

inline void MakeUnique();

Description

Makes the key unique. This ensures that every key value in the index is distinct from every other.

inline TBool IsUnique() const;

Description

Tests whether the key is unique.

Return value

inline void SetComparison(TDbTextComparison aComparison);

Description

Sets the way in which Text columns are compared for the key. All Text columns in the key are compared in the same way.

Parameters

inline TDbTextComparison Comparison() const;

Description

Returns the method used to compare Text columns in this key.

Return value

inline void MakePrimary();

Description

inline TBool IsPrimary() const;

Description

Tests whether the key is the primary key.

Return value

n/a

Description