delphi mysql类_delphi 数据库操作类

最新推荐文章于 2021-03-12 23:58:44 发布

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最新推荐文章于 2021-03-12 23:58:44 发布

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文章标签： delphi mysql类

本文链接：https://blog.youkuaiyun.com/weixin_28982089/article/details/113200367

本文介绍了一个使用Delphi编写的数据库帮助类TDbHelper，该类提供了连接数据库、执行SQL语句、存储过程等功能的方法实现。文章详细展示了如何通过TADOConnection进行数据库交互，并确保了事务的正确处理。

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interface

uses Classes,DB, ADODB,SysUtils,UProcParameter;

type

TDbHelper=class

class function GetANewCon(conString:string):TADOConnection;

private

FAdoCon:TADOConnection;

FConString:string;

function GetAdoCon:TADOConnection;

public

property AdoCon:TADOConnection read GetAdoCon;

function OpenSql(Sql: String): TDataSet;

procedure ExecSql(Sql: String);

procedure ExecSqlTran(SqlList: TStringList);

function IsExistsRec(Sql: String): Boolean;

function GetFirstFieldAsInt(Sql: String): Integer;

function GetFirstFieldAsStr(Sql: String): string;

constructor Create(conString:string);reintroduce;

destructor Destroy;override;

function OpenProc(procName:string;procParams:TProcParameters):TDataSet;

procedure ExecProc(procName: string; procParams: TProcParameters);

end;

implementation

{ TDbHelper }

constructor TDbHelper.Create(conString:string);

begin

inherited Create;

FConString:=conString;

end;

destructor TDbHelper.Destroy;

begin

inherited Destroy;

if Assigned(FAdoCon) then FreeAndNil(FAdoCon);

end;

function TDbHelper.GetAdoCon: TADOConnection;

begin

Result:=FAdoCon;

if not Assigned(FAdoCon) then

FAdoCon:=TAdoConnection.Create(nil);

if not FAdoCon.Connected then

begin

FAdoCon.ConnectionString:=FConString;

FAdoCon.KeepConnection:=True;

FAdoCon.LoginPrompt:=False;

FAdoCon.Open;

end;

Result:=FAdoCon;

end;

class function TDbHelper.GetANewCon(conString: string): TADOConnection;

begin

Result:=TAdoConnection.Create(nil);

Result.ConnectionString:=conString;

Result.KeepConnection:=True;

Result.LoginPrompt:=False;

Result.Open;

end;

function TDbHelper.OpenSql(Sql: String): TDataSet;

var

AQuery:TAdoQuery;

begin

Result:=nil;

AQuery:=TAdoQuery.Create(nil);

AQuery.Connection:=GetAdoCon;

AQuery.SQL.Text:=Sql;

AQuery.Open;

Result:=AQuery;

end;

procedure TDbHelper.ExecSql(Sql: String);

var

AQuery:TAdoQuery;

begin

AQuery:=TAdoQuery.Create(nil);

try

AQuery.Connection:=GetAdoCon;

AQuery.SQL.Text:=Sql;

AQuery.ExecSQL;

finally

AQuery.Close;

FreeAndNil(AQuery);

end;

procedure TDbHelper.ExecSqlTran(SqlList: TStringList);

var

AQuery:TAdoQuery;

Sql:String;

i:Integer;

begin

AQuery:=TAdoQuery.Create(nil);

try

AQuery.Connection:=GetAdoCon;

AQuery.Connection.BeginTrans;

try

for i:=0 to SqlList.Count-1 do

begin

Sql:=SqlList.Strings[i];

AQuery.SQL.Text:=Sql;

AQuery.ExecSQL;

AQuery.Close;

end;

AQuery.Connection.CommitTrans;

except

AQuery.Connection.RollbackTrans;

end;

finally

AQuery.Close;

FreeAndNil(AQuery);

end;

function TDbHelper.IsExistsRec(Sql: String): Boolean;

var

AResSet:TDataSet;

begin

Result:=False;

AResSet:=OpenSql(Sql);

if AResSet<>nil then

begin

Result:=AResSet.RecordCount>0;

AResSet.Close;

FreeAndNil(AResSet);

end;

function TDbHelper.GetFirstFieldAsInt(Sql:String): Integer;

var

AQuery:TAdoQuery;

begin

Result:=-1;

try

AQuery:=TAdoQuery.Create(nil);

AQuery.Connection:=GetAdoCon;

AQuery.SQL.Text:=Sql;

AQuery.Open;

if AQuery.RecordCount>0 then

begin

Result:=AQuery.Fields.Fields[0].AsInteger;

end;

finally

if Assigned(AQuery) then FreeAndNil(AQuery);

end;

function TDbHelper.GetFirstFieldAsStr(Sql: String): String;

var

AQuery:TAdoQuery;

begin

Result:='';

try

AQuery:=TAdoQuery.Create(nil);

AQuery.Connection:=GetAdoCon;

AQuery.SQL.Text:=Sql;

AQuery.Open;

if AQuery.RecordCount>0 then

begin

Result:=AQuery.Fields.Fields[0].AsString;

end;

finally

if Assigned(AQuery) then FreeAndNil(AQuery);

end;

function TDbHelper.OpenProc(procName:string;procParams:TProcParameters):TDataSet;

var

aProc:TADOStoredProc;

aParameter:TProcParameter;

i:Integer;

begin

aProc:=TADOStoredProc.Create(nil);

aProc.Connection:=GetAdoCon;

aProc.ProcedureName:=procName;

for i:=0 to procParams.Count-1 do

begin

aParameter:=procParams.GetParameter(i);

with aProc.Parameters.AddParameter do

begin

Name:=aParameter.Name;

DataType:=aParameter.DataType;

Direction:=aParameter.Direction;

if aParameter.Size<>0 then Size:=aParameter.Size;

Value:=aParameter.Value;

end;

aProc.Open;

Result:=aProc;

end;

procedure TDbHelper.ExecProc(procName:string;procParams:TProcParameters);

var

aProc:TADOStoredProc;

aParameter:TProcParameter;

i:Integer;

begin

aProc:=TADOStoredProc.Create(nil);

try

aProc.Connection:=GetAdoCon;

aProc.ProcedureName:=procName;

for i:=0 to procParams.Count-1 do

begin

aParameter:=procParams.GetParameter(i);

with aProc.Parameters.AddParameter do

begin

Name:=aParameter.Name;

DataType:=aParameter.DataType;

Direction:=aParameter.Direction;

if aParameter.Size<>0 then Size:=aParameter.Size;

Value:=aParameter.Value;

end;

aProc.ExecProc;

for i:=0 to procParams.Count-1 do

begin

aParameter:=procParams.GetParameter(i);

if (aParameter.Direction=pdOutput) or (aParameter.Direction=pdInputOutput) or (aParameter.Direction=pdReturnValue) then

begin

aParameter.Value:=aProc.Parameters[i].Value;

end;

finally

FreeAndNil(aProc);

end;

end.