mini ORM for Delphi
The library is an experiment with RTTI and generics to gain simple, object-oriented access to data from a relational database.
var
ORM : TransfORM;
begin
ORM := TransfORM.Create();
The second step is to define the interface according to the formula:
I[TableName] = interface(ItransfORMEntity)
function [ColumnNameA] : TransfORMField;
function [ColumnNameB] : TransfORMField;
function [ColumnNameC] : TransfORMField;
[...]
end;
...where TableName is the name of the table in the database and ColumnNameA, ColumnNameB etc. are the names of the columns you want to access in the given interface (they do not have to be all).
The last step is to obtain an interface instance containing the data of a specific row from the table. To do this, we call the GetInstance method, giving the value of the primary key.
var
Entity : I[TableName];
PKValue : Integer;
begin
PKValue := 100; //primary key value
Entity := ORM.GetInstance<I[TableName], [PKType]>(PKValue, FDConnection);
In addition to access to the table fields, the entity class also implements methods from the interface:
ItransfORMEntity = interface(IInvokable)
function GetConnection(): TFDConnection;
function GetImmediateCommit(): Boolean;
function HasChanges() : Boolean;
function PrimaryKeyField() : TransfORMField;
procedure Commit(aInSubthread : Boolean = False);
procedure SetImmediateCommit(const aValue: Boolean);
property ImmediateCommit: Boolean read GetImmediateCommit write SetImmediateCommit;
property Connection: TFDConnection read GetConnection;
end;
Current limitations:
- primary key can only be simple key (based on one column)
- data cannot be readed other than via a primary key (e.g. not by a WHERE clause)
The library uses: Spring4D, FireDAC
