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Overview

RTTI providers enable ORM (Object-Relational Mapping) by converting custom Delphi/Pascal classes and records into TDataItem structures and vice versa. Location: BI.RTTI.pas:35,70

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TRTTIProvider

Base class for RTTI-based data providers.

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Constructor

Constructor CreateType(const AOwner: TComponent;
  const AType: PTypeInfo;
  const AVisibility: TVisibility = [mvPublic, mvPublished];
  const AMembers: TRttiMembers = TRttiMembers.Both);
Parameters:
  • AType: Type information for your class/record
  • AVisibility: Which members to include (Public, Published, etc.)
  • AMembers: Fields, Properties, or Both

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Properties

property Members: TRttiMembers;      // Fields, Properties, or Both
property Visibility: TVisibility;    // Member visibility filter

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TTypeProvider<T>

Generic provider with type-safe access to data.

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Constructor

Constructor Create(AOwner: TComponent);
Constructor CreateArray(const AOwner: TComponent; const AValue: array of T);

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Methods

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Add Data

procedure Add(const AValue: T);
procedure Add(const AValue: array of T);
procedure Add(const AValue: TList<T>);
function Add(const AValue: TValue): Integer;

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Access Data

function Count: TInteger;
function Get(const Index: Integer): T;  // or use Items[Index]
property Items[const Index: TInteger]: T;  // Default array property

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Search Data

function Find(const AValue: T): TInteger;  // Returns -1 if not found

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Modify Data

procedure Update(const AIndex: Integer; const AValue: T);
procedure Delete(const AIndex: Integer);
procedure Remove(const AValue: T);
procedure Clear;

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Primary Key

property Primary: TDataItem;  // Designate a primary key field

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Usage Examples

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Define Your Record

type
  TPerson = record
    Name: String;
    Age: Integer;
    City: String;
    Salary: Double;
  end;

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Create Provider

var
  Provider: TTypeProvider<TPerson>;
  Person: TPerson;
begin
  Provider := TTypeProvider<TPerson>.Create(nil);
  try
    // Add data
    Person.Name := 'Alice';
    Person.Age := 30;
    Person.City := 'Madrid';
    Person.Salary := 50000;
    Provider.Add(Person);
    
    Person.Name := 'Bob';
    Person.Age := 25;
    Person.City := 'Barcelona';
    Person.Salary := 45000;
    Provider.Add(Person);
    
    // Access the TDataItem
    BIGrid1.Data := Provider.Data;
    
    // Read back
    Person := Provider[0];  // Get first person
    ShowMessage(Person.Name);
  finally
    Provider.Free;
  end;
end;

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Using Arrays

var
  Provider: TTypeProvider<TPerson>;
  People: array[0..2] of TPerson;
begin
  // Fill array
  People[0].Name := 'Alice';
  People[0].Age := 30;
  
  People[1].Name := 'Bob';
  People[1].Age := 25;
  
  People[2].Name := 'Charlie';
  People[2].Age := 35;
  
  // Create provider from array
  Provider := TTypeProvider<TPerson>.CreateArray(nil, People);
  try
    ShowMessage('Count: ' + IntToStr(Provider.Count));
    BIChart1.Data := Provider.Data;
  finally
    Provider.Free;
  end;
end;

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Using Generic Lists

var
  Provider: TTypeProvider<TPerson>;
  List: TList<TPerson>;
  Person: TPerson;
begin
  List := TList<TPerson>.Create;
  try
    // Add to list
    Person.Name := 'Alice';
    Person.Age := 30;
    List.Add(Person);
    
    // More items...
    
    // Create provider from list
    Provider := TTypeProvider<TPerson>.Create(nil);
    try
      Provider.Add(List);
      BIGrid1.Data := Provider.Data;
    finally
      Provider.Free;
    end;
  finally
    List.Free;
  end;
end;

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Search and Update

var
  Provider: TTypeProvider<TPerson>;
  Person: TPerson;
  Index: Integer;
begin
  Provider := TTypeProvider<TPerson>.Create(nil);
  try
    // Add data...
    
    // Find by value
    Person.Name := 'Alice';
    Index := Provider.Find(Person);
    
    if Index <> -1 then
    begin
      // Update
      Person := Provider[Index];
      Person.Salary := 55000;
      Provider.Update(Index, Person);
    end;
  finally
    Provider.Free;
  end;
end;

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Working with Classes

type
  TEmployee = class
  published
    property Name: String;
    property Department: String;
    property Salary: Double;
  end;

var
  Provider: TTypeProvider<TEmployee>;
  Emp: TEmployee;
begin
  Provider := TTypeProvider<TEmployee>.Create(nil);
  try
    Emp := TEmployee.Create;
    Emp.Name := 'John';
    Emp.Department := 'IT';
    Emp.Salary := 60000;
    
    Provider.Add(Emp);
    BIGrid1.Data := Provider.Data;
  finally
    Provider.Free;
  end;
end;

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Advanced Features

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Nested Records

type
  TAddress = record
    Street: String;
    City: String;
    ZipCode: String;
  end;
  
  TCustomer = record
    Name: String;
    Address: TAddress;  // Nested record
    Balance: Double;
  end;
Nested records are automatically converted to sub-tables in TDataItem.

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Visibility Control

var
  Provider: TRTTIProvider;
begin
  Provider := TRTTIProvider.CreateType(
    nil,
    TypeInfo(TMyClass),
    [mvPublic, mvPublished],  // Only public and published
    TRttiMembers.Properties   // Only properties, not fields
  );
end;

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Performance Tips

  1. Batch Adds: Use array or list overloads instead of adding one by one
  2. Pre-allocate: Use CreateArray when you know the data size
  3. Avoid Find: Use Primary key for faster lookups
  4. Clear vs New: Use Clear to reuse provider instead of Free/Create

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