db.pas

这是不可多得的源代码

    class procedure CheckTypeSize(Value: Integer); override;
    function GetAsBCD: TBcd; override;
    function GetAsBoolean: Boolean; override;
    function GetAsDateTime: TDateTime; override;
    function GetAsFloat: Double; override;
    function GetAsInteger: Longint; override;
    function GetAsSqlTimeStamp: TSQLTimeStamp; override;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetDataSize: Integer; override;
    function GetDefaultWidth: Integer; override;
    procedure GetText(var Text: string; DisplayText: Boolean); override;
    function GetValue(var Value: string): Boolean;
    procedure SetAsBCD(const Value: TBcd); override;
    procedure SetAsBoolean(Value: Boolean); override;
    procedure SetAsDateTime(Value: TDateTime); override;
    procedure SetAsFloat(Value: Double); override;
    procedure SetAsInteger(Value: Longint); override;
    procedure SetAsSQLTimeStamp(const Value: TSQLTimeStamp); override;
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
    property Value: string read GetAsString write SetAsString;
  published
    property EditMask;
    property FixedChar: Boolean read FFixedChar write FFixedChar default False;
    property Size default 20;
    property Transliterate: Boolean read FTransliterate write FTransliterate default True;
  end;

{ TWideStringField }

  TWideStringField = class(TStringField)
  protected
    class procedure CheckTypeSize(Value: Integer); override;
    procedure CopyData(Source, Dest: Pointer); override;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetAsWideString: WideString;
    function GetDataSize: Integer; override;
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
    procedure SetAsWideString(const Value: WideString);
  public
    constructor Create(AOwner: TComponent); override;
    property Value: WideString read GetAsWideString write SetAsWideString;
  end;

{ TNumericField }

  TNumericField = class(TField)
  private
    FDisplayFormat: string;
    FEditFormat: string;
  protected
    procedure RangeError(Value, Min, Max: Extended);
    procedure SetDisplayFormat(const Value: string);
    procedure SetEditFormat(const Value: string);
  public
    constructor Create(AOwner: TComponent); override;
  published
    property Alignment default taRightJustify;
    property DisplayFormat: string read FDisplayFormat write SetDisplayFormat;
    property EditFormat: string read FEditFormat write SetEditFormat;
  end;

{ TIntegerField }

  TIntegerField = class(TNumericField)
  private
    FMinRange: Longint;
    FMaxRange: Longint;
    FMinValue: Longint;
    FMaxValue: Longint;
    procedure CheckRange(Value, Min, Max: Longint);
    procedure SetMaxValue(Value: Longint);
    procedure SetMinValue(Value: Longint);
  protected
    function GetAsFloat: Double; override;
    function GetAsInteger: Longint; override;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetDataSize: Integer; override;
    procedure GetText(var Text: string; DisplayText: Boolean); override;
    function GetValue(var Value: Longint): Boolean;
    procedure SetAsFloat(Value: Double); override;
    procedure SetAsInteger(Value: Longint); override;
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
    property Value: Longint read GetAsInteger write SetAsInteger;
  published
    property MaxValue: Longint read FMaxValue write SetMaxValue default 0;
    property MinValue: Longint read FMinValue write SetMinValue default 0;
  end;

{ TSmallintField }

  TSmallintField = class(TIntegerField)
  protected
    function GetDataSize: Integer; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

{ TLargeintField }

  Largeint = Int64;

  TLargeintField = class(TNumericField)
  private
    FMinValue: Largeint;
    FMaxValue: Largeint;
    procedure CheckRange(Value, Min, Max: Largeint);
  protected
    function GetAsFloat: Double; override;
    function GetAsInteger: Longint; override;
    function GetAsLargeint: Largeint;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetDataSize: Integer; override;
    function GetDefaultWidth: Integer; override;
    procedure GetText(var Text: string; DisplayText: Boolean); override;
    function GetValue(var Value: Largeint): Boolean;
    procedure SetAsFloat(Value: Double); override;
    procedure SetAsInteger(Value: Longint); override;
    procedure SetAsLargeint(Value: Largeint);
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
    property AsLargeInt: LargeInt read GetAsLargeint write SetAsLargeint;
    property Value: Largeint read GetAsLargeint write SetAsLargeint;
  published
    property MaxValue: Largeint read FMaxValue write FMaxValue default 0;
    property MinValue: Largeint read FMinValue write FMinValue default 0;
  end;

{ TWordField }

  TWordField = class(TIntegerField)
  protected
    function GetDataSize: Integer; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

{ TAutoIncField }

  TAutoIncField = class(TIntegerField)
  public
    constructor Create(AOwner: TComponent); override;
  end;

{ TFloatField }

  TFloatField = class(TNumericField)
  private
    FCurrency: Boolean;
    FCheckRange: Boolean;
    FPrecision: Integer;
    FMinValue: Double;
    FMaxValue: Double;
    procedure SetCurrency(Value: Boolean);
    procedure SetMaxValue(Value: Double);
    procedure SetMinValue(Value: Double);
    procedure SetPrecision(Value: Integer);
    procedure UpdateCheckRange;
  protected
    function GetAsFloat: Double; override;
    function GetAsInteger: Longint; override;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetDataSize: Integer; override;
    procedure GetText(var Text: string; DisplayText: Boolean); override;
    procedure SetAsFloat(Value: Double); override;
    procedure SetAsInteger(Value: Longint); override;
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
    property Value: Double read GetAsFloat write SetAsFloat;
  published
    { Lowercase to avoid name clash with C++ Currency type }
    property currency: Boolean read FCurrency write SetCurrency default False;
    property MaxValue: Double read FMaxValue write SetMaxValue;
    property MinValue: Double read FMinValue write SetMinValue;
    property Precision: Integer read FPrecision write SetPrecision default 15;
  end;

{ TCurrencyField }

  TCurrencyField = class(TFloatField)
  public
    constructor Create(AOwner: TComponent); override;
  published
    { Lowercase to avoid name clash with C++ Currency type }
    property currency default True;
  end;

{ TBooleanField }

  TBooleanField = class(TField)
  private
    FDisplayValues: string;
    FTextValues: array[Boolean] of string;
    procedure LoadTextValues;
    procedure SetDisplayValues(const Value: string);
  protected
    function GetAsBoolean: Boolean; override;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetDataSize: Integer; override;
    function GetDefaultWidth: Integer; override;
    procedure SetAsBoolean(Value: Boolean); override;
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
    property Value: Boolean read GetAsBoolean write SetAsBoolean;
  published
    property DisplayValues: string read FDisplayValues write SetDisplayValues;
  end;

{ TDateTimeField }

  TDateTimeField = class(TField)
  private
    FDisplayFormat: string;
    function GetValue(var Value: TDateTime): Boolean;
    procedure SetDisplayFormat(const Value: string);
  protected
    procedure CopyData(Source, Dest: Pointer); override;
    function GetAsDateTime: TDateTime; override;
    function GetAsFloat: Double; override;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetDataSize: Integer; override;
    function GetDefaultWidth: Integer; override;
    procedure GetText(var Text: string; DisplayText: Boolean); override;
    procedure SetAsDateTime(Value: TDateTime); override;
    procedure SetAsFloat(Value: Double); override;
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
    property Value: TDateTime read GetAsDateTime write SetAsDateTime;
  published
    property DisplayFormat: string read FDisplayFormat write SetDisplayFormat;
    property EditMask;
  end;

{ TSQLTimeStampField }

  TSQLTimeStampField = class(TField)
  private
    FDisplayFormat: string;
    function GetValue(var Value: TSQLTimeStamp): Boolean;
    procedure SetDisplayFormat(const Value: string);
  protected
    procedure CopyData(Source, Dest: Pointer); override;
    function GetAsSQLTimeStamp: TSQLTimeStamp; override;
    function GetAsDateTime: TDateTime; override;
    function GetAsFloat: Double; override;
    function GetAsString: string; override;
    function GetAsVariant: Variant; override;
    function GetDataSize: Integer; override;
    function GetDefaultWidth: Integer; override;
    procedure GetText(var Text: string; DisplayText: Boolean); override;
    procedure SetAsSQLTimeStamp(const Value: TSQLTimeStamp); override;
    procedure SetAsDateTime(Value: TDateTime); override;
    procedure SetAsFloat(Value: Double); override;
    procedure SetAsString(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
    property Value: TSQLTimeStamp read GetAsSQLTimeStamp write SetAsSQLTimeStamp;
  published
    property DisplayFormat: string read FDisplayFormat write SetDisplayFormat;
    property EditMask;
  end;

{ TDateField }

  TDateField = class(TDateTimeField)
  protected
    function GetDataSize: Integer; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

{ TTimeField }

  TTimeField = class(TDateTimeField)
  protected
    function GetDataSize: Integer; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

{ TBinaryField }

  TBinaryField = class(TField)
  protected
    class procedure CheckTypeSize(Value: Integer); override;
    procedure CopyData(Source, Dest: Pointer); override;
    function GetAsString: string; override;
    procedure GetText(var Text: string; DisplayText: Boolean); override;
    function GetAsVariant: Variant; override;
    procedure SetAsString(const Value: string); override;
    procedure SetText(const Value: string); override;
    procedure SetVarValue(const Value: Variant); override;
  public
    constructor Create(AOwner: TComponent); override;
  published
    property Size default 16;
  end;

{ TBytesField }

  TBytesField = class(TBinaryField)
  protected
    function GetDataSize: Integer; override;
  public
    constructor Create(AOwner: TComponent); override;
  end;

{ TVarBytesField }

  TVarBytesField = class(TBytesField)
  protected
    function GetDataSize: Integer; override;