Read IndexDefs to obtain information about what indexes are available on the database server for this dataset. 

TCustomSQLDataSet does not explicitly use the information in IndexDefs. The order of its records is determined by the ORDER BY clause of its SQL statement. 

If the SQL dataset is an instance of TSQLTable, you can use IndexDefs to identify the index to use for the IndexName property. Even with other TCustomSQLDataSet descendants, IndexDefs can be useful for composing SQL commands dynamically that need to use an index on the server. For example, provider components use the index information to uniquely identify records when composing update commands. 

TIndexDef 

SortFieldNames 

CommandText 

SQL 

TDataSetProvider 

IndexName 

GetKeyFieldNames