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如何使用 Delphi 7 在 SQL Server 2012 上更新 DateTime 保留毫秒ADOQuery.ExecSQL？

DateTime2[7]SQL Server 似乎降低了秒精度，所以我在 SQL Server 2012字段上没有毫秒或微秒。MS Access 不会使用此 ADO 查询减少毫秒数。以下 ADOQuery 代码似乎适用于我关心的所有 DataTypes 除了 SQL Server DateTime。

我正在使用的连接字符串是： Provider=SQLNCLI11.1;Integrated Security=SSPI;User ID="";Initial File Name="";Server SPN="";Data Source=myPC\SQLSERVER2012EXP;Initial Catalog=MyDatabase

这是我的代码：

function ExecuteNonQry(Conn:TADOConnection;Sql:string;Params:Variant): Integer;
{ Execute a query that does not return a recordset.  Returns number of rows 
  affected. Params can be any unique name, they are all dealt with in order
  of appearance in the parameter array and in the sql string.
  E.g. SQL 
    'INSERT INTO customers (id,name,country) VALUES (:id,:name,:country)';
  E.g. calling code:
    sql := 
     'INSERT INTO Sessions (SessionType_cod , HasErrors, Start_Timestamp) ' + 
     ' VALUES (:1, :2, :3)';
    params := VarArrayOf([ 1, true, Now ]);
    ExecuteNonQry( GvConnection1, sql, params );

    Note: Do not use ADO with Paradox - will be slow and possibly error prone.

    Tested the following DataTypes with "Insert Into" and "Update" queries
    **********************************************************************
    Delphi          MS Access    SQL Server      Paradox
    -----------------------------------------------------
    ftInteger       Long         int
    ftString        Text(255)    nvarchar(255)
    ftString        Memo         nvarchar(max)
    ftBoolean       Boolean      bit
    ftDateTime      Date         datetime2(7)
    ftDouble        Double       float
}
var
  qry : TADOQuery;
begin
  assert( Conn <> nil);
  assert( Sql <> '');
  qry := TADOQuery.Create(nil);
  qry.DisableControls;
  qry.SQL.Text := Sql;
  AddParametersToQuery(qry, Params);
  qry.Connection := Conn;
  result := qry.ExecSQL;
end;

procedure AddParametersToQuery(var Qry: TADOQuery; Params: Variant);
{ Version 1b.  (Uses Delphi function to replace "DIRegEx" dependencies)
  Add parameters (type and value) to ADO query. ADOQuery must have SQL 
  text set and Params is a variant array. 
  Limitations: SQL Server drops DateTime second precision digits for 
  milliseconds or microseconds.
  E.g. Sql: 
    'INSERT INTO Sessions (SessionType_cod , HasErrors, Start_Timestamp) 
     VALUES (:1, :2, :3)';
  or  Sql: 
    'INSERT INTO Sessions (SessionType_cod , HasErrors, Start_Timestamp) 
     VALUES (:mykey, :HasErrors, :myDateTime)';
}
const
  regPattern = ':';
var
  str: String;
  val: Variant;
  i: Integer;
  sl: TStrings;
begin
  assert( Qry.SQL.Text <> '');

  // in some cases this is necessary.
  Qry.Parameters.ParseSQL(Qry.SQL.Text, true);        

  sl := TStringList.Create;
  try
    // find all param wordssql text such as '1, 2, 3'
    sl := ExtractWordsToStrings(':', Qry.SQL.Text);   

    // loop through any matches found
    for i := 0 to sl.Count -1 do            
    begin
      str := sl[i];
      val := GetVarParam(i, Params);
      // in some cases this is necessary.
      Qry.Parameters.ParamByName(str).DataType := 
          VarTypeToDataType(Ord(VarType(val)) );
      Qry.Parameters.ParamByName(str).Value := val;
    end;
  finally
    sl.Free;
  end;
end;

更新

MS Access 和 SQL Server 的修改代码：

if (VarType(val) = varDate) And IsSqlServerProvider(Conn.Provider) then begin
  // needed for SQL Server
  Qry.Parameters.ParamByName(str).Value := 
     FormatDateTime('yyyymmdd hh:nn:ss.zzz', val)   
end
else
begin
  // in some cases this is necessary.
  Qry.Parameters.ParamByName(str).DataType := 
     VarTypeToDataType(Ord(VarType(val))); 
  Qry.Parameters.ParamByName(str).Value := val;
end;
4

1 回答 1

7

通过 Ado 的 DateTime2(7) 被视为 TWideStringField。
日期时间将被视为 TDateTimeField。
如果分配 TDatetime，内部转换将忽略像 DateTimeToStr(dt) 这样的毫秒。
您可以使用自己的转换为 WideString 来处理这个问题。

Function MyDateTimeString(d:TDateTime):String;
begin
  Result := FormatDateTime('yyyymmdd hh:nn:ss.zzz',d);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
dt:TdateTime;
begin
  dt := now;
  Caption := FormatDateTime('dd.mm.yyyy hh:nn:ss.zzz',dt);
  Adoquery1.Paramcheck := true;
  Adoquery1.SQL.Text := 'Insert into Tab (a,b,DT) Values (:a,:b,:DT)';
  Adoquery1.Parameters.ParseSQL(Adoquery1.SQL.Text,true);
  Adoquery1.Parameters.ParamByName('a').Value := 1;
  Adoquery1.Parameters.ParamByName('b').Value := 2;
  Adoquery1.Parameters.ParamByName('DT').Value := MyDateTimeString(dt);
  Adoquery1.ExecSQL;
end;

使用 then 以下将导致四舍五入：

  Adoquery1.Parameters.ParamByName('DT').DataType := ftDateTime;
  Adoquery1.Parameters.ParamByName('DT').Value := dt;
于 2013-01-12T07:54:04.753 回答