SQLdb Tutorial3

• • • work in progress; to do: finish me ***

Using any database and a login form.

advantages: - user/programmer can dynamically use any sqldb t*connection, so he can choose between dbs

disadvantages - more complicated SQL will likely need to still be adapted - you can't use T*connection specific properties (like TIBConnection.Dialect to set Firebird dialect). - complicates code some

to do: Expand this code to also show a form if needed for user input and do arguments handling from command line. Also perhaps create a non-gui version to do: get ludob's version from the forum, IIRC that was a form based thingy. <syntaxhighglight> unit dbconfig;

{ Small unit that retrieves connection settings for your database

 Copyright (c) 2012 Reinier Olislagers

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to
 deal in the Software without restriction, including without limitation the
 rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 sell copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 IN THE SOFTWARE.

}

//todo: add command line support (--dbtype=, --db=, --dbhost=, dbuser=, dbpass=, dbcharset= {$mode objfpc}{$H+}

interface

uses

 Classes, SysUtils, IniFiles;

type

 { TDBConnectionConfig }
 TDBConnectionConfig = class(TObject)
 private
   FDBCharset: string;
   FDBType: string;
   FDBHost: string;
   FDBPath: string;
   FDBUser: string;
   FDBPassword: string;
   FSettingsFileIsRead: boolean; //indicates if we read in settings file
   FSettingsFile: string;
   function GetDBCharset: string;
   function GetDBHost: string;
   function GetDBPassword: string;
   function GetDBPath: string;
   function GetDBType: string;
   function GetDBUser: string;
   function GetDefaultSettingsFile:string;
   procedure ReadINIFile;
   procedure SetDBType(AValue: string);
   procedure SetSettingsFile(AValue: string);
 public
   property DBCharset: string read GetDBCharset write FDBCharset; //Character set used for database (e.g. UTF8)
   property DBHost: string read GetDBHost write FDBHost; //Database host/server (name or IP address). Leave empty for embedded
   property DBPath: string read GetDBPath write FDBPath; //Path/database name
   property DBUser: string read GetDBUser write FDBUser; //User name needed for database (e.g. sa, SYSDBA)
   property DBPassword: string read GetDBPassword write FDBPassword; //Password needed for user name
   property DBType: string read GetDBType write SetDBType; //Type of database connection, e.g. Firebird, Oracle
   property SettingsFile: string read FSettingsFile write SetSettingsFile; //ini file to read settings from. If empty defaults to <programname>.ini
   constructor Create;
   constructor Create(DefaultType:string; DefaultHost:string=; DefaultPath:string='data.fdb';
     DefaultUser:string='SYSDBA'; DefaultPassword:string='masterkey'; DefaultCharSet:string='UTF8');
   destructor Destroy; override;
 end;

implementation

{ TDBConnectionConfig }

function TDBConnectionConfig.GetDBHost: string; begin

 if not(FSettingsFileIsRead) then ReadINIFile;
 result:=FDBHost;

end;

function TDBConnectionConfig.GetDBCharset: string; begin

 if not(FSettingsFileIsRead) then ReadINIFile;
 result:=FDBCharset;

end;

function TDBConnectionConfig.GetDBPassword: string; begin

 if not(FSettingsFileIsRead) then ReadINIFile;
 result:=FDBPassword;

end;

function TDBConnectionConfig.GetDBPath: string; begin

 if not(FSettingsFileIsRead) then ReadINIFile;
 result:=FDBPath;

end;

function TDBConnectionConfig.GetDBType: string; begin

 if not(FSettingsFileIsRead) then ReadINIFile;
 result:=FDBType;

end;

function TDBConnectionConfig.GetDBUser: string; begin

 if not(FSettingsFileIsRead) then ReadINIFile;
 result:=FDBUser;

end;

function TDBConnectionConfig.GetDefaultSettingsFile:string; begin

 result:=ChangeFileExt(ParamStr(0), '.ini');

end;

procedure TDBConnectionConfig.SetSettingsFile(AValue: string); begin

 // If empty value given, use the program name
 if AValue= then AValue:=GetDefaultSettingsFile;
 if FSettingsFile=AValue then Exit;
 FSettingsFile:=AValue;
 // Read from file if present
 ReadINIFile;

end;

procedure TDBConnectionConfig.SetDBType(AValue: string); begin

 if FDBType=AValue then Exit;
 case UpperCase(AValue) of
   'FIREBIRD': FDBType:='Firebird';
   'POSTGRES', 'POSTGRESQL': FDBType:='PostgreSQL';
   'SQLITE','SQLITE3': FDBType:='SQLite';
 else FDBType:=AValue;
 end;

end;

procedure TDBConnectionConfig.ReadINIFile; var

 INI: TIniFile;

begin

 if FileExists(FSettingsFile) then
 begin
   INI := TINIFile.Create(FSettingsFile);
   try
     FDBType := INI.ReadString('Database', 'DatabaseType', FDBType); //Default to Firebird
     FDBHost := INI.ReadString('Database', 'Host', FDBHost);
     FDBPath := INI.ReadString('Database', 'Database', FDBPath);
     FDBUser := INI.ReadString('Database', 'User', 'SYSDBA');
     FDBPassword := INI.ReadString('Database', 'Password', 'masterkey');
     FSettingsFileIsRead:=true;
   finally
     INI.Free;
   end;
 end;

end;

constructor TDBConnectionConfig.Create; begin

 inherited Create;
 // Defaults
 FSettingsFile:=GetDefaultSettingsFile;
 FSettingsFileIsRead:=false;
 FDBType := 'Firebird';
 FDBHost := ; //embedded
 FDBPath := 'data.fdb';
 FDBUser := 'SYSDBA';
 FDBPassword := 'masterkey';

end;

constructor TDBConnectionConfig.Create(DefaultType:string; DefaultHost:string=; DefaultPath:string='data.fdb';

 DefaultUser:string='SYSDBA'; DefaultPassword:string='masterkey'; DefaultCharSet:string='UTF8');

begin

 create;
 FDBCharset:=DefaultCharset;
 FDBHost:=DefaultHost;
 FDBPassword:=DefaultPassword;
 FDBPath:=DefaultPath;
 FDBType:=DefaultType;
 FDBUser:=DefaultUser;

end;

destructor TDBConnectionConfig.Destroy; begin

 inherited Destroy;

end;

end. </syntaxhighglight>

add section on creating dbs here, handy for embedded (sqlite, firebird); also do firebird c/s to contrast