Eval'uate the function...
-- DROP TABLE Table1
-- DROP TABLE Table2
CREATE TABLE [Table1] (
[Name] [char] (10) NOT NULL ,
[Oper] [char] (50) NOT NULL ,
CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED
(
[Name]
) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [Table2] (
[ID] [int] NOT NULL ,
[Value1] [int] NOT NULL ,
[Value2] [int] NOT NULL ,
CONSTRAINT [PK_Table2] PRIMARY KEY CLUSTERED
(
[ID]
) ON [PRIMARY]
) ON [PRIMARY]
GO
INSERT INTO [Contratos].[dbo].[Table1]([Name], [Oper]) VALUES('Multiply', 'Value1 * Value2')
INSERT INTO [Contratos].[dbo].[Table1]([Name], [Oper]) VALUES('Add', 'Value1 + Value2')
INSERT INTO [Contratos].[dbo].[Table2]([ID], [Value1], [Value2]) VALUES(1, 5, 10)
INSERT INTO [Contratos].[dbo].[Table2]([ID], [Value1], [Value2]) VALUES(2, 75, 710)
DECLARE @internal_function VARCHAR(520)
SELECT @internal_function = Oper FROM Table1 WHERE Name = 'Multiply'
EXEC('select ' + @internal_function + ' as total from Table2 where ID = 2')
ADO.NET Calling ...
Still don't know how to recover the 'eval' result from a stored proc :(
Dim c As New System.Data.SqlClient.SqlConnection("application name=Temp;data source=(local);initial catalog=Temp;password" & _
"=MyPassword;persist security info=True;user id=sa;workstation id=SUEPRSDEV;packet size=4096")
c.Open()
Dim d As New System.Data.SqlClient.SqlCommand()
d.Connection = c
d.CommandText = "" + _
"DECLARE @internal_function VARCHAR(520)" + vbCrLf + _
"SELECT @internal_function = Oper FROM Table1 WHERE Name = 'Multiply'" + vbCrLf + _
"EXEC('select ' + @internal_function + ' as total from Table2 where ID = 2')" ' PROVIDE THE ID
d.CommandType = CommandType.Text
Dim r As System.Data.SqlClient.SqlDataReader = d.ExecuteReader(CommandBehavior.SingleResult)
r.Read()
Debug.Write(r.GetValue(0))
Im not encourage you to do silly things :)
This should be very well implemented.
Dont allow the user to insert the 'Function' or some other 'genius-ly' thing.
Good luck!
Hackman
