Parameterized upsert command over odbc doesn´t work - mysql

Question

i have a problem with doing parameterized upsert commands over odbc.
Thats the upsert command
Dim upsert As New OdbcCommand
upsert.Connection = connection
upsert.CommandText = "
INSERT INTO products_replacement
(products_model, products_replacement)
VALUES
(#products_model, #products_replacement)
ON DUPLICATE KEY UPDATE products_replacement = #products_replacement;
"
upsert.Parameters.Add("#products_replacement", OdbcType.VarChar)
upsert.Parameters.Add("#products_model", OdbcType.VarChar)
For Each Product In ListOfProducts
upsert.Parameters.Item("#products_replacement").Value = Product.Value
upsert.Parameters.Item("#products_model").Value = Product.Key
upsert.ExecuteNonQuery()
NEXT
Error message: "ERROR [HY000] [MySQL][ODBC 5.1 Driver][mysqld-5.7.30]Column 'products_model' cannot be null"
In the Debugger the values of the parameters are correctly set.
Something like that works
upsert.Commandtext = upsert.Commandtext.Replace("#products_replacement", $"'{Product.Value}'").Replace("#products_model", $"'{Product.Key}'")
upsert.ExecuteNonQuery()
ListOfProducts is a Dictionary(Of String, String)
Error handling and other stuff is stripped from my above example code.
Parameterized querys are prefered and i had no problems doing the same with MS SQL...
What am I missing?
Help is appreciated.

Answer 1

ODBC doesn't use named parameters
You can give them names in the SQL, but you should then imagine that they all get transformed into ? and are treated positionally by the driver; the name is meaningless
This means you need to add as many parameters to your VB Command.Parameters collection as your statement contains, even if it means repeating values - you cannot reuse VB parameters them by repeating the name in the SQL. The name is still semi useful in VB for indexing purposes:
Dim upsert As New OdbcCommand
upsert.Connection = connection
upsert.CommandText = "
INSERT INTO products_replacement
(products_model, products_replacement)
VALUES
(?, ?)
ON DUPLICATE KEY UPDATE products_replacement = ?;
"
upsert.Parameters.Add("#pmod", OdbcType.VarChar)
upsert.Parameters.Add("#prep1", OdbcType.VarChar)
upsert.Parameters.Add("#prep2", OdbcType.VarChar)
For Each Product In ListOfProducts
upsert.Parameters.Item("#pmod").Value = Product.Value
upsert.Parameters.Item("#prep1").Value = Product.Key
upsert.Parameters.Item("#prep2").Value = Product.Key
upsert.ExecuteNonQuery()
NEXT