当表具有默认列返回时PDO插入列数与第1行的值数不匹配

Question

I've created a database table of four columns, where two of the four are columns to not be updated. For example

Database columns:

• sessionID = auto increment mysql column
• userID = data to be passed in
• IP = data to be passed in
• timeSession = default value of CURRENT_TIMESTAMP() in mysql column

So since two of these columns are to be filled with data, and two are not, I am only inserting the two values needed like so using PDO:

$d = [
   'userID' => $userID,
   'IP' => Helper::getIP()
];
$qry = "INSERT INTO {$this->tableName} VALUES (:userID,:IP)";
        $sth = $this->getConnection()->prepare($qry);
        $sth->execute($d);

When running this query, I get the following error: Column count doesn't match value count at row 1 . I have to manually set values for both sessionID and timeSession to make my insert work - which defeats the entire purpose of having an auto incrementing field and a field that auto populates in my database.

Do I have to modify my PDO logic to account for these two "special" tables? What am I missing here?

Answer 1

You have four columns, but you specified only 2 in the VALUES section. You need to list their names after the table name and omit the ones which should be defaulted.

INSERT INTO {$this->tableName} (userID, IP) VALUES (:userID,:IP)

If you want to list the default columns, but let the values be defaulted then you can use the keyword DEFAULT

INSERT INTO {$this->tableName} (userID, IP, timeSession ) VALUES (:userID, :IP, DEFAULT)

When inserting a new row, the default value for a column with an expression default can be inserted either by omitting the column name or by specifying the column as DEFAULT (just as for columns with literal defaults) - MySQL Docs

Answer 2

I like the alternative INSERT syntax that MySQL supports:

INSERT INTO {$this->tableName} SET userID = :userID, IP = :IP

It's easier to read, matches up the columns with the parameter placeholders, and it also solves the issue you're having when you don't want to specify a value for certain columns.

The downsides are:

• It's non-standard syntax, not supported by most other SQL brands.
• It doesn't support inserting multiple rows in a single INSERT statement.