# The C++ Index Class

The Index class represents a database table index.

### For an overview see page C++ Classes

The Index methods are listed below.

bool isApplicable( SearchOperation op, int nRanges, Range ranges[] ) | Check if the Index is applicable for the specified ranges. This method is used internally by the eXtremeSQL runtime to determine when a search index can be used (Note that it can also be used if the developer is implementing a custom data source (virtual table) interface)
bool isOrdered( void ) | Check if the Index performs a sort in key order; returns `true` if the index is ordered, `false` if not ordered or unknown
bool isUnique( void ) | Check if the Index is unique
Iterator <Key>* keys( void ) | Create an iterator for all Key fields in this Index