CODEWITHSUNDEEP
c#.netmysqlsqlmysql-parameter
Adam Lassek
Adam Lassek

Reputation: 35505

How do I conditionally set a column to its default value with MySqlParameter?

I have a table in a MySql database that stores user accounts. One of the columns, expires, stores an expiration date but defaults to NULL. I need to be able to remove an expiration date and set it back to the default value.

Currently, all of my CRUD routines are written using MySqlCommand with parameters. Can this be done directly with a MySqlParameter, or do I have to create an alternate command object to handle this eventuality?

Upvotes: 2

Views: 1447

Answers (3)

JYelton
JYelton

Reputation: 36512

I usually set values that are intended to be default/blank to null in code, then before executing the query, run the following loop:

foreach(MySqlParameter param in cmd.Parameters)
    if (param.Value == null) param.Value = DBNull.Value;

Upvotes: 0

Adam Lassek
Adam Lassek

Reputation: 35505

The problem was DBNull, doing:

command.Parameters.AddWithValue("@parameter", null);

compiles OK.

Upvotes: 3

aku
aku

Reputation: 123974

It's not clear what conditions you're talking about. If you want to set column to default value, you can use DbNull.Value;

command.AddWithValue("@param", DbNull.Value);

or

command.Parameters.Add("@param", <data type>).Value = DBNull.Value;

Upvotes: 0

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