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PostgresException: 42804 when executing several queries with parameters with one open connection #6067
Description
Activity
As a workaround, you can specify the name of the parameter before adding it to the collection.
private static IDbDataParameter AddParameter(this IDbCommand command) { IDbDataParameter parameter = command.CreateParameter(); var index = command.Parameters.Count; parameter.ParameterName = index.ToString(CultureInfo.InvariantCulture); command.Parameters.Add(parameter); return parameter; }
The problem is that because when the parameter is added for the first time it doesn't have a name, it's considered as positional (unnamed), and it seems like we do not react that well whenever their name is changed.
I think removing
_caseInsensitiveLookup.Count == 0check from here should do the trick?npgsql/src/Npgsql/NpgsqlParameterCollection.cs
Lines 146 to 147 in 22a0aa9
cc @NinoFloris
Reacted by HoMS1987Thx, this workaround really helped :)
- added a commit that references this issue
on Mar 26, 2025 - marked Named parameter mapping breaks with more than 5 parameters using the same DbConnection twice #6081 as a duplicate of this issue
on Mar 28, 2025
When executing Queries with parameters on the same table, I get the error:
Npgsql.PostgresException: 42804: Column »bool1« has Type boolean but expression has type integer
But when debugging the datatype of the NpgsqlParameter is correct, directly before I call ExecuteNonQuery()
I attached a little test project, that reproduces this error.
Only the connection string inside has to be adjustet.
It creates a new database, a new table and first tries to update a row (which is not still there) and as it couldn't update the row it creates it.
During the creation of this row the Exception is thrown.
NpgsqlTest.zip