'Declaration
Public MustInherit Class SQLiteAggregateFunction
(Of T1,T2,T3,T4,TResult)
Inherits SQLiteAggregateFunction
Implements System.IDisposable
public abstract class SQLiteAggregateFunction<T1,T2,T3,T4,TResult> : SQLiteAggregateFunction, System.IDisposable
Use this class to derive user-defined aggregate functions with four parameters 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 SQLiteAggregateFunction to create user-defined aggregate functions with any number of parameters.
The result of an aggregate function is a scalar object, but its value is accumulated when processing query result records. It is executed for each record, and its result can be accumulated. Average, Summ, or Count are the examples of such functions.
To register the user-defined aggregate funtion, create the class, derived from SQLiteAggregateFunction and pass its name and number of arguments to the base class constructor.
You should also override Step and Complete methods. Step method should implement the way of acumulating and storing result, and Complete method should process the accumulated value after all records were processed.
System.Object
Devart.Data.SQLite.SQLiteFunction
Devart.Data.SQLite.SQLiteAggregateFunction
Devart.Data.SQLite.SQLiteAggregateFunction<T1,T2,T3,T4,TResult>