Question

这是我写一个select语句来检查数据库中是否有值的方法。

bool userIsPresent=false;
string sqlQuery = string.Format("SELECT * FROM Person WHERE Name = '{0}'", name);

SqlCommand s = new SqlCommand(sqlQuery, con);
con.Open();

SqlDataReader sqlread = s.ExecuteReader();
userIsPresent = sqlread.HasRows;
con.Close();

但现在我需要将一些值保存到数据库中。我怎样才能做到这一点？我不认为我应该使用SqlDataReader，那么如何保存并确认数据是否已保存到数据库中？

public static bool saveToDb(string name1,string nam2, DateTime dat)
{
    bool ok=false;
    string sqlQuery = string.Format("INSERT into NumbersTable values ('{0}', '{1}','{2}')",name1,nam2,dat );

    SqlCommand s = new SqlCommand(sqlQuery, con);

    con.Open();
    SqlDataReader sr = s.ExecuteReader(); // MIGHT BE WRONG
    ok = sr.HasRows;

    con.Close();
    return ok;
}

Answer 1

您需要ExecuteNonQuery才能在数据库中插入记录。

s.ExecuteNonQuery();

（使用Parameterized query阻止SQL注入）

Answer 2

好的，所以你要做的是插入数据库而不是从中读取，因此你必须简单地在数据库上执行sql查询而不读取从中选择的任何数据。为此，您需要使用ExecuteNonQuery语句而不是sqlDataReader。结果看起来像这样

public static bool saveToDb(string name1, string nam2, DateTime dat)
{
  bool ok = false;
  string sqlQuery = "INSERT INTO NumbersTable VALUES (@name1, @nam2, @dat)";
  //This is the sql query we will use and by placing the @ symbol in front of words
  //Will establish them as variables and placeholders for information in an sql command
  //Next we create the sql command
  SqlCommand cmd = new SqlCommand(sqlQuery, con);
  //Here we will insert the correct values into the placeholders via the commands
  //parameters
  cmd.Parameters.AddWithValue("name1", name1);
  //This tells it to replace "@name1" with the value of name1
  cmd.Parameters.AddWithValue("nam2", nam2);
  cmd.Parameters.AddWithValue("dat", dat);
  //Finally we open the connection
  con.Open();
  //Lastly we tell the sql command to execute on the database, in this case inserting
  //the values
  int i = cmd.ExecuteNonQuery();
  //Here we have the results of the execution stored in an integer, this is because
  //ExecuteNonQuery returns the number of rows it has effected, in the case of this
  //Insert statement it would effect one row by creating it, therefore i is 1
  //This is useful for determining if your sql statement was successfully executed
  //As if it returns 0, nothing has happened and something has gone wrong
  con.Close();
}

我希望这有帮助，如果你需要别的东西可以随意问。

Answer 3

在您的代码中添加：

con.open();
S.executeNonQuery();

Answer 4

试试吧......这段代码会给出正确的信息..
name1，name2，dat是数据库

中数据表中的列名

public static void saveToDb（）
  {
     string sqlQuery =“INSERT into NumbersTable（name1，name2，dat）values（'Princee'，'Singhal'，'18/02/2012'）;
      SqlCommand s = new SqlCommand（sqlQuery，con）;
      con.Open（）;
      int i = s.ExecuteNonQuery（）;
      如果（I＆GT; = 1）
      {
         MessageBox.Show（“Record Inserted”）;
      }
      否则
      {
         MessageBox.Show（“可能会出现一些问题！”）;
      }
      con.Close（）;
  }

Answer 5

只需要纠正现有代码中的某些内容，这肯定会对您有所帮助：

 public static bool executeMyQuery(string sqlQuery)
      {
        try
        {        con.Open();
                 SqlCommand s = new SqlCommand(sqlQuery, con);
                 s.ExecuteNonQuery();
                 con.Close();
                 return true;
         } 
       catch()
        {
          return false;
        }

    And use the above function[executeMyQuery()] anywhere you want to insert like and check whether record is inserted or not like below:

     bool isInserted = false;
     // give dummy value or get it what u want to inser on name1,nam2,dat
     string rawQuery = string.Format("INSERT into NumbersTable values ('{0}', '{1}','{2}')",name1,nam2,dat );

    isInserted = myExecuteQuery(rawQuery);

  if(isInserted)
    { 
      // lblStatus i am taking only to make you understand
      // lblStatus.text = "Record inserted succesfully";
    }
  else
    {
       // lblStatus.text = "Record insertion failed";
    }

使用SqlDataReader将值插入SQL Server表

5 个答案: