You use a DbDataAdapter to populate a DataTable. You need to ensure that when the DbDataAdapter loads the DataTable, it sets the DataColumn.MaxLength and DataColumn.ReadOnly properties to correspond to data source-defined constraints.

What should you do?

Setting DbDataAdapter.MissingSchemaAction to MissingSchemaAction.AddWithKey configures the following DataColumn properties if they exist at the data source: AllowDBNull, AutoIncrement, MaxLength, ReadOnly, and Unique.

The DataAdapter.MissingSchemaAction property is used to specify whether missing source tables, columns, and their relationships are added to the data set schema, are ignored, or cause an error to be raised. Setting DbDataAdapter.MissingSchemaAction to MissingSchemaAction.Add does not add schema information like column MaxLength and ReadOnly constraints.