Data.DB.TUnsignedAutoIncField
Delphi
TUnsignedAutoIncField = class(TLongWordField)
C++
class PASCALIMPLEMENTATION TUnsignedAutoIncField : public TLongWordField
Properties
Type | Visibility | Source | Unit | Parent |
---|---|---|---|---|
class | public | Data.DB.pas Data.DB.hpp |
Data.DB | Data.DB |
Description
TUnsignedAutoIncField is a persistent field object for an auto-increment unsigned integer value field in a dataset.
TUnsignedAutoIncField provides access to an auto-increment field in a table. Auto-increment fields can hold values in the range from 0 through 4,294,967,295, and are used as a counter for the records in the dataset. Each record is given a unique value in an auto-increment field, with each record receiving the next highest integer from that of the previously inserted record. Auto-increment fields are commonly used to provide a unique primary key value for a record.
Note: Auto-incrementing fields are a function of the database back-end. An application should not attempt to set a field value for an auto-increment field (with or without a TUnsignedAutoIncField object).
If you use the Fields editor at design time to create a persistent field component for the auto-incrementing field, you can access it by name at run time. When using dynamic field components, you can access the TUnsignedAutoIncField instance using the dataset's Fields property or FieldByName method.