Added support SQLExpression operator overloading. Closes #52.

Provides the powerful ability to generate SQL expressions for arithmetic operations and string concatenation using regular .NET code. Any arithmetic operator or string concatenation can be applied to an SQLExpression and the appropriate operator is translated into the appropriate SQL command. This significantly simplifies the .NET code and also simplifies the process of generating the SQL code, because normal .NET operators can be utilised.

For example: "New SQLFieldExpression("Field") Mod 10" translates to SQL "([Field] % 10)". The expression can be used in an SQLSelect, SQLInsert, SQLDelete or SQLUpdate class (amongst others).

SQL/Expressions/SQLExpression.vb

@@ -15,6 +15,204 @@ Namespace SQL
 
         Friend MustOverride Function SQL(ByVal eConnectionType As Database.ConnectionType) As String
 
+        Public Shared Operator +(left As SQLExpression, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Add, right)
+
+        End Operator
+
+        Public Shared Operator +(left As SQLExpression, right As Decimal) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Add, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator +(left As Decimal, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(New SQLValueExpression(left), ArithmeticOperator.Add, right)
+
+        End Operator
+
+        Public Shared Operator +(left As SQLExpression, right As DateTime) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Add, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator +(left As DateTime, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(New SQLValueExpression(left), ArithmeticOperator.Add, right)
+
+        End Operator
+
+        Public Shared Operator +(left As String, right As SQLExpression) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(New SQLValueExpression(left), right)
+
+        End Operator
+
+        Public Shared Operator +(left As SQLExpression, right As String) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(left, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator +(left As SQLStringConcatExpression, right As SQLExpression) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(left, right)
+
+        End Operator
+
+        Public Shared Operator +(left As SQLExpression, right As SQLStringConcatExpression) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(left, right)
+
+        End Operator
+
+        Public Shared Operator &(left As String, right As SQLExpression) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(New SQLValueExpression(left), right)
+
+        End Operator
+
+        Public Shared Operator &(left As SQLExpression, right As String) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(left, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator &(left As SQLStringConcatExpression, right As SQLExpression) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(left, right)
+
+        End Operator
+
+        Public Shared Operator &(left As SQLExpression, right As SQLStringConcatExpression) As SQLStringConcatExpression
+
+            Return New SQLStringConcatExpression(left, right)
+
+        End Operator
+
+        Public Shared Operator -(left As SQLExpression, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Subtract, right)
+
+        End Operator
+
+        Public Shared Operator -(left As SQLExpression, right As Decimal) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Subtract, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator -(left As Decimal, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(New SQLValueExpression(left), ArithmeticOperator.Subtract, right)
+
+        End Operator
+
+        Public Shared Operator -(left As SQLExpression, right As DateTime) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Subtract, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator -(left As DateTime, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(New SQLValueExpression(left), ArithmeticOperator.Subtract, right)
+
+        End Operator
+
+        Public Shared Operator *(left As SQLExpression, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Multiply, right)
+
+        End Operator
+
+        Public Shared Operator *(left As SQLExpression, right As Decimal) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Multiply, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator *(left As Decimal, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(New SQLValueExpression(left), ArithmeticOperator.Multiply, right)
+
+        End Operator
+
+        Public Shared Operator /(left As SQLExpression, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Divide, right)
+
+        End Operator
+
+        Public Shared Operator /(left As SQLExpression, right As Decimal) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Divide, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator /(left As Decimal, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(New SQLValueExpression(left), ArithmeticOperator.Divide, right)
+
+        End Operator
+
+        Public Shared Operator Mod(left As SQLExpression, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Modulus, right)
+
+        End Operator
+
+        Public Shared Operator Mod(left As SQLExpression, right As Decimal) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(left, ArithmeticOperator.Modulus, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator Mod(left As Decimal, right As SQLExpression) As SQLArithmeticExpression
+
+            Return New SQLArithmeticExpression(New SQLValueExpression(left), ArithmeticOperator.Modulus, right)
+
+        End Operator
+
+        Public Shared Operator Or(left As SQLExpression, right As SQLExpression) As SQLBitwiseExpression
+
+            Return New SQLBitwiseExpression(left, BitwiseOperator.Or, right)
+
+        End Operator
+
+        Public Shared Operator Or(left As SQLExpression, right As Decimal) As SQLBitwiseExpression
+
+            Return New SQLBitwiseExpression(left, BitwiseOperator.Or, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator Or(left As Decimal, right As SQLExpression) As SQLBitwiseExpression
+
+            Return New SQLBitwiseExpression(New SQLValueExpression(left), BitwiseOperator.Or, right)
+
+        End Operator
+
+        Public Shared Operator And(left As SQLExpression, right As SQLExpression) As SQLBitwiseExpression
+
+            Return New SQLBitwiseExpression(left, BitwiseOperator.And, right)
+
+        End Operator
+
+        Public Shared Operator And(left As SQLExpression, right As Decimal) As SQLBitwiseExpression
+
+            Return New SQLBitwiseExpression(left, BitwiseOperator.And, New SQLValueExpression(right))
+
+        End Operator
+
+        Public Shared Operator And(left As Decimal, right As SQLExpression) As SQLBitwiseExpression
+
+            Return New SQLBitwiseExpression(New SQLValueExpression(left), BitwiseOperator.And, right)
+
+        End Operator
+
     End Class
 
 End Namespace