SQLiteAggregateFunction<T1,T2,T3,T4,T5,T6,T7,T8,TResult> Class

In This Topic

Generic base class for user-defined aggregate functions with four parameters.

Syntax

Visual Basic
C#

'Declaration
 
Public MustInherit Class SQLiteAggregateFunction
    (Of T1,T2,T3,T4,T5,T6,T7,T8,TResult) 
   Inherits SQLiteAggregateFunction
   Implements System.IDisposable

public abstract class SQLiteAggregateFunction<T1,T2,T3,T4,T5,T6,T7,T8,TResult> : SQLiteAggregateFunction, System.IDisposable

Type Parameters

T1: Type of the first user-defined function parameter.
T2: Type of the second user-defined function parameter.
T3: Type of third the user-defined function parameter.
T4: Type of the fourth user-defined function parameter.
T5: Type of the fifth user-defined function parameter.
T6: Type of the sixth user-defined function parameter.
T7: Type of the seventh user-defined function parameter.
T8: Type of the eighth user-defined function parameter.
TResult: Type of the user-defined function result.

Remarks

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.

Inheritance Hierarchy

System.Object
   Devart.Data.SQLite.SQLiteFunction
      Devart.Data.SQLite.SQLiteAggregateFunction
         Devart.Data.SQLite.SQLiteAggregateFunction<T1,T2,T3,T4,T5,T6,T7,T8,TResult>

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

Reference

SQLiteAggregateFunction<T1,T2,T3,T4,T5,T6,T7,T8,TResult> Members
Devart.Data.SQLite Namespace

Send Feedback