Changeset 6 for trunk/UDatabase.pas

Timestamp:

Jan 20, 2015, 12:31:24 AM (9 years ago)

Author:

chronos

Message:

• Added: Allow to create multiple database connections and set their parmaters.
• Added: Defined database engines to support various database backends. Each supports different set of field data types.

File:

• trunk/UDatabase.pas (modified) (4 diffs)

trunk/UDatabase.pas

@@ -10 +10 @@
 type
   TTable = class;
+  TDatabaseEngine = class;
 
   TFieldType = (ftString, ftInteger, ftDateTime, ftBoolean, ftFloat, ftImage,
@@ -109 +110 @@
     Tables: TTables;
     ConnectionString: string;
+    Engine: TDatabaseEngine;
     constructor Create;
     destructor Destroy; override;
@@ -115 +117 @@
   end;
 
+  TDatabases = class(TObjectList)
+
+  end;
+
+  TDatabaseClass = class of TDatabase;
+
+  { TDataType }
+
+  TDataType = class
+    Name: string;
+    FieldType: TFieldType;
+  end;
+
+  TDataTypes = class(TObjectList)
+    function RegisterType(Name: string; FieldType: TFieldType): TDataType;
+  end;
+
+  { TDatabaseEngine }
+
+  TDatabaseEngine = class
+    Name: string;
+    DataTypes: TDataTypes;
+    DatabaseClass: TDatabaseClass;
+    constructor Create;
+    destructor Destroy; override;
+  end;
+
+  { TDatabaseEngines }
+
+  TDatabaseEngines = class(TObjectList)
+    function RegisterEngine(Name: string; DatabaseClass: TDatabaseClass): TDatabaseEngine;
+    function FindByName(Name: string): TDatabaseEngine;
+  end;
+
 
 implementation
@@ -120 +156 @@
 uses
   UDataTypes;
+
+{ TDatabaseEngines }
+
+function TDatabaseEngines.RegisterEngine(Name: string;
+  DatabaseClass: TDatabaseClass): TDatabaseEngine;
+begin
+  Result := TDatabaseEngine.Create;
+  Result.Name := Name;
+  Result.DatabaseClass := DatabaseClass;
+  Add(Result);
+end;
+
+function TDatabaseEngines.FindByName(Name: string): TDatabaseEngine;
+var
+  I: Integer;
+begin
+  I := 0;
+  while (I < Count) and (TDatabaseEngine(Items[I]).Name <> Name) do Inc(I);
+  if I < Count then Result := TDatabaseEngine(Items[I])
+    else Result := nil;
+end;
+
+{ TDataTypes }
+
+function TDataTypes.RegisterType(Name: string; FieldType: TFieldType): TDataType;
+begin
+  Result := TDataType.Create;
+  Result.Name := Name;
+  Result.FieldType := FieldType;
+  Add(Result);
+end;
+
+{ TDatabaseEngine }
+
+constructor TDatabaseEngine.Create;
+begin
+  DataTypes := TDataTypes.Create;
+end;
+
+destructor TDatabaseEngine.Destroy;
+begin
+  DataTypes.Free;
+  inherited Destroy;
+end;
 
 { TValues }