C＃MySQL声称字段太长

Question

Here's the SQL:

CREATE TABLE patients 
(
  patient_id INT AUTO_INCREMENT NOT NULL,
  last_name  VARCHAR(64) NOT NULL,
  first_name VARCHAR(64),
  sex        CHAR(1),
  birth      DATE,
  death      DATE,
  PRIMARY KEY (patient_id)
) ENGINE=INNODB;

And here's the C#:

            MySqlCommand insertCom = new MySqlCommand("INSERT INTO patients(" +
                "last_name, first_name, sex, birth) VALUES" + 
                "('@lastName', '@firstName', '@sex', '@birthDate')",
                connection);

            /* ... */
            insertCom.Parameters.Add("@lastName", MySqlDbType.VarChar, 64);
            insertCom.Parameters.Add("@firstName", MySqlDbType.VarChar, 64);
            insertCom.Parameters.Add("@sex", MySqlDbType.Char, 1);
            insertCom.Parameters.Add("@birthDate", MySqlDbType.Date);

            insertCom.Parameters["@lastName"].Value = lastNameBox.Text; 
            insertCom.Parameters["@firstName"].Value = firstNameBox.Text;
            insertCom.Parameters["@sex"].Value = (sexBox.Text == "Male" ? 'M' : 'F');
            insertCom.Parameters["@birthDate"].Value = birthDatePicker.Text;

This is how I enter data directly in SQL:

INSERT INTO patients(last_name, first_name, sex, birth, death) 
VALUES
  ('DeLarge', 'Alexandra', 'F', '1975-12-02', NULL)

The above works and I wrote the C# code based on that. But the C# code produces this: MySql.Data.MySqlClient.MySqlException: Data too long for column 'sex' at row 1 . What gives?

Answer 1

You should not have single quotes around the parameter names. Try it like this instead:

MySqlCommand insertCom = new MySqlCommand("INSERT INTO patients(" +
            "last_name, first_name, sex, birth) VALUES" + 
            "(@lastName, @firstName, @sex, @birthDate)",
            connection);

Answer 2

Ahah, found your problem. I think your MySQL should be :

MySqlCommand("INSERT INTO patients(" +
                "last_name, first_name, sex, birth) VALUES" + 
                "(@lastName, @firstName, @sex, @birthDate)"

Because what you're trying to insert is ('DeLarge', 'Alexandra', 'F', '1975-12-02', NULL) But, your command dictates to insert : ('@lastName', '@firstName', '@sex', '@birthDate') And MySQL is catching that the value '@sex' is too big to fit in a single character

Take out the ' from your command and let C# handle all the datatypes and formatting itself.