Unable to process TVP when 1st row contains null on varchar

Hello,

We are running the code below in Python (3.8) using pytds version 1.11.0 and I am receiving the error message “pytds.tds_base.OperationalError: The incoming tabular data stream (TDS) remote procedure call (RPC) protocol stream is incorrect. Table-valued parameter 5 (""), row 2, column 6: Data type 0xE7 has an invalid data length or metadata length.”

Looking at the error it seems that colums 6 in row 2 is exceeding the data type size, however, if I revers the order of the rows, this code runs successfully.

It looks like the None value provided on the first row is causing the issue, since replacing this None by an empty string is making the code to run without any problem.

I have also tried to use callproc method instead of execute, but it is returnining the same error.

The expected behaviour is to accept the None value and proceed with the others rows without any problem since all of them are complient with the type definition.

Supporting code:

CREATE TYPE MySchema.MyUserStoredProcedureDataType AS TABLE(
	[Column_001] [varchar](500) NULL,
	[Column_002] [varchar](500) NOT NULL,
	[Column_003] [varchar](500) NULL,
	[Column_004] [varchar](500) NOT NULL,
	[Column_005] [tinyint] NOT NULL,
	[Column_006] [varchar](500) NULL,
	[Column_007] [datetime2](2) NOT NULL
)

import pytds
import datetime

sql_statement = """EXEC MySchema.MyUserStoredProcedure
                            @Data = %(tvp)s,
                            @EventUUID = %(event_uuid)s,
                            @UserUUID = %(user_uuid)s;"""


array_tvp = [
      ['d191affd66e4d8ef1cd14a368cc3b920', 'SOME TEXT ROW 1 COLUMN 2', 'SOME TEXT ROW 1 COLUMN 3', 'SOME TEXT ROW 1 COLUMN 4', 100, None, datetime.datetime(2021, 5, 7, 21, 32, 45)]
    , ['7b61f7245e1f5bf0d17f0d14ad57339d', 'SOME TEXT ROW 2 COLUMN 2', 'SOME TEXT ROW 2 COLUMN 3', 'SOME TEXT ROW 2 COLUMN 4', 1, 'd191affd66e4d8ef1cd14a368cc3b920', datetime.datetime(2021, 5, 7, 21, 32, 45)]
]
with conn.cursor() as cursor:

    logger.info('Execute SQL statement for MySchema.MyUserStoredProcedure')
    cursor.execute(
        operation=sql_statement,
        params={
            "tvp": pytds.TableValuedParam(
                type_name='MySchema.MyUserStoredProcedureDataType',
                rows=array_tvp
            ),
            "event_uuid": '2ca5a8df-27de-4fc9-b8bd-314f64af420c',
            "user_uuid": '29c1da9b-661d-4bc8-a24a-c4f60155b8fd'
        }
    )
    cursor.get_proc_return_status()

    logger.info('Execute SQL statement for MySchema.MyUserStoredProcedure successfully executed')

Thanks in advance for your help!

[takoau]

@baresh561 @jdiaz-merkle made 2 helper functions to find out user data types and populate a list of Column objects:

def getType(tvtName, cursor):
    from pytds.tds_base import Column
    parser = pytds.tds_types.DeclarationsParser()
    rs = cursor.execute("SELECT name, system_type_name, is_nullable FROM sys.dm_exec_describe_first_result_set('SELECT * FROM @test', N'@test " + tvtName + " READONLY', 0) ORDER BY column_ordinal").fetchall()
    return [Column(name=row[0], type=parser.parse(row[1]), flags = row[2] & Column.fNullable) for row in rs]

array_tvp = [
    [None, 'SOME TEXT ROW 1 COLUMN 2', 'SOME TEXT ROW 1 COLUMN 3', 'SOME TEXT ROW 1 COLUMN 4', 100, '1', datetime.datetime(2021, 5, 7, 21, 32, 45)]
    , ['7b61f7245e1f5bf0d17f0d14ad57339d', 'SOME TEXT ROW 2 COLUMN 2', 'SOME TEXT ROW 2 COLUMN 3', 'SOME TEXT ROW 2 COLUMN 4', 1, 'd191affd66e4d8ef1cd14a368cc3b920', datetime.datetime(2021, 5, 7, 21, 32, 45)]
]

#  getType() to get column list from user-defined types and getTable() for tables
with conn.cursor() as cursor:
    columns = getType("testType", cursor)
with conn.cursor() as cursor:
    cursor.execute(
        operation=sql_statement,
        params={
            "tvp": pytds.TableValuedParam(
                type_name='testType',
                columns=columns,
                rows=array_tvp)
        }
    )

[takoau]

@baresh561 @jdiaz-merkle Knowing it has been late for years. pytds estimates column type by checking first row of data. Column type default to be nvarchar(1) If data in first column is None. Hence error is thrown if data succeeding is not nvarchar(1).