VistaDB 5






Column's name
The initial identity value. This value may be evaluated throw v-expression
The step value to use for identity. The step may be evaluated throw v-expression
DefineIdentity Method
Assign the identity to the column.
Syntax
'Declaration
 
Sub DefineIdentity( _
   ByVal columnName As System.String, _
   ByVal seedValue As System.String, _
   ByVal stepExpression As System.String _
) 
'Usage
 
Dim instance As IVistaDBTableSchema
Dim columnName As System.String
Dim seedValue As System.String
Dim stepExpression As System.String
 
instance.DefineIdentity(columnName, seedValue, stepExpression)
void DefineIdentity( 
   System.string columnName,
   System.string seedValue,
   System.string stepExpression
)
procedure DefineIdentity( 
    columnName: System.String;
    seedValue: System.String;
    stepExpression: System.String
); 
function DefineIdentity( 
   columnName : System.String,
   seedValue : System.String,
   stepExpression : System.String
);
void DefineIdentity( 
   System.string* columnName,
   System.string* seedValue,
   System.string* stepExpression
) 
void DefineIdentity( 
   System.String^ columnName,
   System.String^ seedValue,
   System.String^ stepExpression
) 

Parameters

columnName
Column's name
seedValue
The initial identity value. This value may be evaluated throw v-expression
stepExpression
The step value to use for identity. The step may be evaluated throw v-expression
Remarks
VistaDB supports identity for the Int16, Int32 and Int64 data types only. The identity counter does not participate transactions, thus it ensures unique value is assigned to the column in multi-user environment. Note, the engine doesn't check existing rows for the column values, so setting identity doesn't check unique numbers. You may set the unique index on this column, to ensure you have unique values from an identity.
Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

See Also