SQLiteScalarFunction<T1,TResult> Class

In This Topic

Base class for user-defined scalar functions with one parameter.

Syntax

Visual Basic
C#

'Declaration
 
Public MustInherit Class SQLiteScalarFunction
    (Of T1,TResult) 
   Inherits SQLiteScalarFunction
   Implements System.IDisposable

public abstract class SQLiteScalarFunction<T1,TResult> : SQLiteScalarFunction, System.IDisposable

Type Parameters

T1: Type of the user-defined function parameter.
TResult: Type of the user-defined function result.

Remarks

Use this generic class to derive classes for user-defined scalar functions with one parameter from it. This generic class was introduced to ease the user-defined function creating. It allows to specify parameter count, type, and function result type. As an alternative, you may use SQLiteScalarFunction to create user-defined aggregate functions with any number of parameters.

The scalar function is a simple function, that returns a scalar value and is executed once when called.

To register the user-defined scalar funtion, create the class, derived from SQLiteScalarFunction and pass its name and number of arguments to the base class constructor.

You should also override the Execute(T1,SQLiteConnection) method, which should implement the function actions.

Example

Here is an example of creating of the function, that calculates the square root.

csharp

public class MyFunction : SQLiteScalarFunction<double, double> {

        public MyFunction()
        : base("Sqrt") {
        }

        protected override double Execute(double arg1, SQLiteConnection connection) {
      
                return Math.Sqrt(arg1);
        }
}

Inheritance Hierarchy

System.Object
   Devart.Data.SQLite.SQLiteFunction
      Devart.Data.SQLite.SQLiteScalarFunction
         Devart.Data.SQLite.SQLiteScalarFunction<T1,TResult>

Reference

SQLiteScalarFunction<T1,TResult> Members
Devart.Data.SQLite Namespace

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