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使用FireDAC的TFDManager和TFDConnection组件实现运行时动态数据库连接

news 2026/5/12 18:37:11

以下是一个通用的数据库连接方案，使用FireDAC的TFDManager和TFDConnection组件实现运行时动态数据库连接。支持多种数据库类型，采用面向对象封装：

unit DatabaseManager;interfaceusesSystem.SysUtils, System.Classes, FireDAC.Stan.Intf, FireDAC.Stan.Option,FireDAC.Stan.Error, FireDAC.UI.Intf, FireDAC.Phys.Intf, FireDAC.Stan.Def,FireDAC.Stan.Pool, FireDAC.Stan.Async, FireDAC.Phys, FireDAC.Comp.Client,FireDAC.Stan.Param, FireDAC.DatS, FireDAC.DApt.Intf, FireDAC.DApt, Data.DB,FireDAC.Comp.DataSet;typeTDatabaseType = (dtSQLite, dtMySQL, dtPostgreSQL, dtMSSQL, dtOracle);TDatabaseManager = classprivateFConnection: TFDConnection;FManager: TFDManager;FDatabaseType: TDatabaseType;FLastError: string;procedure ValidateDriver;function GetConnectionDefName: string;function GetDriverName: string;function BuildParams(Params: TStrings): string;publicconstructor Create;destructor Destroy; override;procedure ConfigureConnection(DatabaseType: TDatabaseType; Params: TStrings);function Connect: Boolean;procedure Disconnect;function ExecSQL(const SQL: string; Params: TArray<TVarRec>): Integer;function OpenQuery(const SQL: string; Params: TArray<TVarRec>): TFDQuery;property LastError: string read FLastError;end;implementation{ TDatabaseManager }constructor TDatabaseManager.Create;
beginFManager := TFDManager.Create(nil);FConnection := TFDConnection.Create(nil);FManager.SilentMode := True;FManager.Active := True;
end;destructor TDatabaseManager.Destroy;
beginDisconnect;FConnection.Free;FManager.Free;inherited;
end;procedure TDatabaseManager.ConfigureConnection(DatabaseType: TDatabaseType; Params: TStrings);
beginFDatabaseType := DatabaseType;FManager.ConnectionDefs.Clear;// 添加新的连接定义FManager.AddConnectionDef(GetConnectionDefName,GetDriverName,BuildParams(Params));
end;function TDatabaseManager.Connect: Boolean;
beginResult := False;tryValidateDriver;FConnection.ConnectionDefName := GetConnectionDefName;FConnection.Connected := True;Result := True;FLastError := '';excepton E: Exception doFLastError := '连接失败: ' + E.Message;end;
end;procedure TDatabaseManager.Disconnect;
beginif FConnection.Connected thenFConnection.Connected := False;
end;function TDatabaseManager.ExecSQL(const SQL: string; Params: TArray<TVarRec>): Integer;
varQuery: TFDQuery;
beginResult := -1;Query := TFDQuery.Create(nil);tryQuery.Connection := FConnection;Query.SQL.Text := SQL;if Length(Params) > 0 thenQuery.MacroByName('params').Value := Params;Query.ExecSQL;Result := Query.RowsAffected;finallyQuery.Free;end;
end;function TDatabaseManager.OpenQuery(const SQL: string; Params: TArray<TVarRec>): TFDQuery;
beginResult := TFDQuery.Create(nil);tryResult.Connection := FConnection;Result.SQL.Text := SQL;if Length(Params) > 0 thenResult.MacroByName('params').Value := Params;Result.Open;exceptResult.Free;raise;end;
end;// 私有方法实现
procedure TDatabaseManager.ValidateDriver;
begincase FDatabaseType ofdtSQLite: FDPhysSQLiteDriverLink.Create(nil);dtMySQL: FDPhysMySQLDriverLink.Create(nil);dtPostgreSQL: FDPhysPgDriverLink.Create(nil);dtMSSQL: FDPhysMSSQLDriverLink.Create(nil);dtOracle: FDPhysOracleDriverLink.Create(nil);end;
end;function TDatabaseManager.GetConnectionDefName: string;
beginResult := Format('%s_Connection', [GetEnumName(TypeInfo(TDatabaseType), Ord(FDatabaseType))]);
end;function TDatabaseManager.GetDriverName: string;
begincase FDatabaseType ofdtSQLite: Result := 'SQLite';dtMySQL: Result := 'MySQL';dtPostgreSQL: Result := 'PG';dtMSSQL: Result := 'MSSQL';dtOracle: Result := 'Ora';elseraise Exception.Create('不支持的数据库类型');end;
end;function TDatabaseManager.BuildParams(Params: TStrings): string;
varI: Integer;
beginResult := '';for I := 0 to Params.Count - 1 doResult := Result + Format('%s=%s;', [Params.Names[I], Params.ValueFromIndex[I]]);
end;end.

使用示例：

// 创建数据库管理器
varDB: TDatabaseManager;Params: TStringList;Query: TFDQuery;
beginDB := TDatabaseManager.Create;try// 配置SQLite连接Params := TStringList.Create;tryParams.Values['Database'] := 'C:\Data\mydb.sqlite';Params.Values['OpenMode'] := 'CreateUTF8';DB.ConfigureConnection(dtSQLite, Params);finallyParams.Free;end;if DB.Connect thenbegin// 执行SQL命令DB.ExecSQL('CREATE TABLE IF NOT EXISTS Users (ID INTEGER PRIMARY KEY, Name TEXT)');// 执行查询Query := DB.OpenQuery('SELECT * FROM Users');trywhile not Query.Eof dobeginShowMessage(Query.FieldByName('Name').AsString);Query.Next;end;finallyQuery.Free;end;endelseShowMessage(DB.LastError);finallyDB.Free;end;
end;

功能特点：

多数据库支持：
- 支持SQLite、MySQL、PostgreSQL、SQL Server和Oracle
- 通过TDatabaseType枚举轻松扩展新数据库类型
动态配置：
安全连接管理：
- 自动验证数据库驱动
- 内置错误处理机制
- 连接资源自动释放
灵活的参数化查询：
事务支持（可扩展）：

配置参数说明：

数据库类型	必需参数	示例值
SQLite	Database, OpenMode	Database=C:\data\test.sdb
MySQL	Server, Database, User_Name, Password	Server=192.168.1.100;Port=3306
PostgreSQL	Server, Database, User_Name, Password	Port=5432
MSSQL	Server, Database, User_Name, Password	OSAuthent=Yes
Oracle	Server, User_Name, Password	ServiceName=ORCL