As implemented in TDataSet, this property is false if the dataset is unidirectional, and true otherwise. Descendant classes reimplement this property as follows 

For unidirectional datasets, CanModify is always false. 

For client datasets, CanModify reflects the value of the ReadOnly property and whether a data provider supplied a read-only data packet. 

Other datasets reflect whether the dataset has write access to data. 

DataSource 

AutoEdit 

ReadOnly 

Editing Data in a Control 

Editing in the Grid 

Adding New Records 

Controlling Read/Write Access to Tables 

Editing Records 

Using Unidirectional Datasets