C# guid and SQL uniqueidentifier

Question

I want to create a GUID and store it in the DB.

In C# a guid can be created using Guid.NewGuid(). This creates a 128 bit integer. SQL Server has a uniqueidentifier column which holds a huge hexidecimal number.

Is there a good/preferred way to make C# and SQL Server guids play well together? (i.e. create a guid using Guid.New() and then store it in the database using nvarchar or some other field ... or create some hexidecimal number of the form that SQL Server is expecting by some other means)

Answer 1

There is a SQL type for this: uniqueidentifier.

Answer 2

SQL is expecting the GUID as a string. The following in C# returns a string Sql is expecting.

"'" + Guid.NewGuid().ToString() + "'"

Something like

INSERT INTO TABLE (GuidID) VALUE ('4b5e95a7-745a-462f-ae53-709a8583700a')

is what it should look like in SQL.

Answer 3

Store it in the database in a field with a data type of uniqueidentifier.

Answer 4

It's far better to use stored procedures to communicate with your SQL database, in which case you'd declare the parameter type as OleDbType.Guid and pass a C# value of type Guid.

If you must construct SQL strings, you can surround it with single quotes as previously mentioned.

Answer 5

Here's a code snipit showing how to insert a Guid using a parametrised query:

    using(SqlConnection conn = new SqlConnection(connectionString))
    {
        conn.Open();
        using(SqlTransaction trans = conn.BeginTransaction())
        using (SqlCommand cmd = conn.CreateCommand())
        {
            cmd.Transaction = trans;
            cmd.CommandText = @"INSERT INTO [MYTABLE] ([GuidValue]) VALUE @guidValue;";
            cmd.Parameters.AddWithValue("@guidValue", Guid.NewGuid());
            cmd.ExecuteNonQuery();
            trans.Commit();
        }
    }