Sql Connection not inserting data

Question

I'm currently working on writing an error logging program that will take a connection string and a table name and insert the data that I provide it from other programs into a database. The problem that I'm facing though is that my method doesn't return any values and nothing is loaded into the database. This is a standard class library as well

public string ErrorLevelOne(string ConnectionString, string TableName, string ProjectName, string exception, string stackTrace)
        {
            try
            {
                SqlConnection conn = new SqlConnection(ConnectionString);
                conn.Open();
                string query = "INSERT INTO" + TableName + "(ErrorType, StackTrace, OccuranceTime)";
                query += "Values (@ErrorType, @StackTrace, @OccuranceTime, @ProjectName)";
                SqlCommand command = new SqlCommand(query, conn);
                command.Parameters.AddWithValue("@ErrorType", exception);
                command.Parameters.AddWithValue("@StackTrace", stackTrace);
                command.Parameters.AddWithValue("@OccuranceTime", DateTime.Now);
                command.Parameters.AddWithValue("@ProjectName", ProjectName);
                command.ExecuteNonQuery();
                conn.Close();

                return "Error has been posted into the database";
            }
            catch(Exception err)
            {
                Debug.WriteLine("Error in connecting or inserting  data into " + TableName + ": " + err.Message);
                return "Error hasn't been posted into the database";
            }
        }

Any help or suggestions would be greatly appreciated.

The problem that I'm facing though is that my method doesn't return any values and nothing is loaded into the database; command.ExecuteNonQuery() would return how many rows were affected, you're not assigning anything to this. Are there any errors, have you debugged your code, please edit your post. — Trevor
– Trevor, Commented Apr 7, 2020 at 16:12

STALER · Accepted Answer · 2020-04-07 16:12:47Z

1

I wanted to write a comment but there is not enough reputation, I apologize. In this line you do not have spaces before the variable TableName

"INSERT INTO" + TableName + "(ErrorType, StackTrace, OccuranceTime)";

In the end, you get it

"INSERT INTOTableName(ErrorType...'

Also, you do not have the square brackets '[~]' in the table specification

@"INSERT INTO [ {TableName} ]..."

Also check your connectionString for errors, and does catch throw anything?

If this does not help, write, I will try to help :)

answered Apr 7, 2020 at 16:12

STALER

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1 Comment

Dominik Willaford Over a year ago

I have included the space after INTO as well as the brackets around TableName, but I'm still getting the same null reference as I was before. I have checked to ensure my connection string is correct.

Marc Gravell · Accepted Answer · 2020-04-07 16:12:53Z

1

Look at the exception message. Your SQL is wrong - it is missing a space:

string query = "INSERT INTO " + TableName + @"(ErrorType, StackTrace, OccuranceTime)
Values (@ErrorType, @StackTrace, @OccuranceTime, @ProjectName)";

See the space after the INTO ? As a side note, it is usually a bad idea to parameterize the table name; that seems very... unusual. If you must do that, it may be worth comparing it against a list of known-permitted values (or perhaps take an enum on the API, and worry about the name inside the method), and you should also use [] syntax:

string tableName  = GetTableName(errorTableEnumThing);
string query = "INSERT INTO [" + tableName + @"](ErrorType, StackTrace, OccuranceTime)
Values (@ErrorType, @StackTrace, @OccuranceTime, @ProjectName)";

answered Apr 7, 2020 at 16:12

Marc Gravell

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2 Comments

Dominik Willaford Over a year ago

Hello Marc, I have included the space after INTO as well as the brackets around TableName, but I'm still getting the same null reference as I was before. I have checked to ensure my connection string is correct.

Marc Gravell Over a year ago

@DominikWillaford you realize this is the first time you've mentioned a null reference, right? What line?

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