Delphi - 查询运行缓慢

Question

我的查询,运行大约需要7秒才能完成应该的操作.但是,由于它插入了大约30条记录,我认为它太慢了.现在,要么我运行的查询写得不好,要么实际需要这么多时间.但那会很奇怪.底层数据库是SQLite,查询如下所示:

procedure TForm1.cxButton1Click(Sender: TObject);
begin
with UNIquery2 do begin
  Close;
  SQL.Clear;
UNIQuery1.First;
while Uniquery1.EOF = false do begin
SQL.Text:= 'INSERT INTO MYTABLE (FIELD1,FIELD2,FIELD3,FIELD4) VALUES (:a1,:a2,:a3,:a4)';
         ParamByName('a1').asString := AdvOfficeStatusBar1.Panels[0].Text;
         ParamByName('a2').asString := UniTable1.FieldByName('FIELD2').asString;
         ParamByName('a3').asString := Uniquery1.FieldByName(',FIELD3').asString;
         ParamByName('a4').Value := Uniquery1.FieldByName('FIELD4').Value;//boolean field true/false
         Uniquery1.Next;
         ExecSQL;
end;
end;
end;

那么有人可以告诉我这是否正常或我错过了什么？所有字段都是文本,除了'a4',它是布尔值(true/false).

答案,修改(基于来自LS_dev的提取):

procedure TForm1.cxButton1Click(Sender: TObject);
begin
    with UNIquery2 do begin
        Close;
        SQL.Clear;
        SQL.Add('INSERT INTO MYTABLE (FIELD1,FIELD2,FIELD3,FIELD4) VALUES (:a1,:a2,:a3,:a4)');
        SQL.Prepare;
        UniTransaction.AddConnection(UniConnection2);
        UniTransaction.StartTransaction;
try
        UNIQuery1.First;
        while Uniquery1.EOF = false do begin
            Params[0].asString := AdvOfficeStatusBar1.Panels[0].Text;
            Params[1].asString := UniTable1.FieldByName('FIELD2').asString;
            Params[2].asString := Uniquery1.FieldByName(',FIELD3').asString;
            Params[3].Value := Uniquery1.FieldByName('FIELD4').Value;//boolean field true/false
            Uniquery1.Next;
            ExecSQL;
        end;
        UniTransaction.Commit;
finally
  if UNIquery2.Connection.InTransaction then
    UNIquery2.Connection.Rollback;
    end;
    end;
    end;

Answer 1

不知道Delphi,但会提出一些改进:

1. 您没有使用交易.COMMIT所有插入后你应该有类似自动提交禁用和命令之类的东西;

2. 你的SQL.Text:=...应该可能不合时宜.如果此属性集编译SQL语句,则将其置于while之外将防止不必要的VDBE编译;

3. 如果您的意图是将行从一个表复制到另一个表(使用静态字段),则可以使用单个SQL命令,例如INSERT INTO MYTABLE SELECT :a1, FIELD2, FIEDL3, FIELD4 FROM source_table,设置ParamByName('a1').asString := AdvOfficeStatusBar1.Panels[0].Text

这是通用的DB使用改进,希望给你一些指导.

使用唯一SQL的建议:

procedure TForm1.cxButton1Click(Sender: TObject);
begin
    with UNIquery2 do
    begin
        SQL.Clear;
        SQL.Add('INSERT INTO MYTABLE (FIELD1,FIELD2,FIELD3,FIELD4) SELECT ?,FIELD2,FIELD3,FIELD4 FROM UNIquery1_source_table');
        Params[0].asString := AdvOfficeStatusBar1.Panels[0].Text;
        ExecSQL;
    end;
end;

建议使用改进的数据库处理:

procedure TForm1.cxButton1Click(Sender: TObject);
begin
    with UNIquery2 do 
    begin
        Close;
        SQL.Clear;
        SQL.Add('INSERT INTO MYTABLE (FIELD1,FIELD2,FIELD3,FIELD4) VALUES (:a1,:a2,:a3,:a4)');
        SQL.Prepare;
        UniTransaction.AddConnection(UniConnection2);
        UniTransaction.StartTransaction;
        UNIQuery1.First;
        while Uniquery1.EOF = false do 
        begin
            Params[0].asString := AdvOfficeStatusBar1.Panels[0].Text;
            Params[1].asString := UniTable1.FieldByName('FIELD2').asString;
            Params[2].asString := Uniquery1.FieldByName(',FIELD3').asString;
            Params[3].Value := Uniquery1.FieldByName('FIELD4').Value;//boolean field true/false
            Uniquery1.Next;
            ExecSQL;
        end;
        UniTransaction.Commit;
    end;
end;