Used to specify the data source component which binds current dataset to the master one.
property MasterSource: TDataSource;
The MasterSource property specifies the data source component which binds current dataset to the master one.
TCustomDADataset uses MasterSource to extract foreign key fields values from the master dataset when building master/detail relationship between two datasets. MasterSource must point to another dataset; it cannot point to this dataset component.
When MasterSource is not nil dataset fills parameter values with corresponding field values from the current record of the master dataset.
Note: Do not set the DataSource property when building master/detail relationships. Although it points to the same object as the MasterSource property, it may lead to undesirable results.