How to insert 'NULL' values for 'int' column tupes in Aurora PostgreSQL db using Python boto3 client - postgresql

Question

I have a CSV file (MS SQL server table export) and I would like to import it to Aurora Serverless PostgreSQL database table. I did a basic preprocessing of the CSV file to replace all of the NULL values in it (i.e. '') to "NULL". The file looks like that:
CSV file:
ID,DRAW_WORKS
10000002,NULL
10000005,NULL
10000004,FLEXRIG3
10000003,FLEXRIG3
The PostgreSQL table has the following schema:
CREATE TABLE T_RIG_ACTIVITY_STATUS_DATE (
ID varchar(20) NOT NULL,
DRAW_WORKS_RATING int NULL
)
The code I am using to read and insert the CSV file is the following:
import boto3
import csv
rds_client = boto3.client('rds-data')
...
def batch_execute_statement(sql, sql_parameter_sets, transaction_id=None):
parameters = {
'secretArn': db_credentials_secrets_store_arn,
'database': database_name,
'resourceArn': db_cluster_arn,
'sql': sql,
'parameterSets': sql_parameter_sets
}
if transaction_id is not None:
parameters['transactionId'] = transaction_id
response = rds_client.batch_execute_statement(**parameters)
return response
transaction = rds_client.begin_transaction(
secretArn=db_credentials_secrets_store_arn,
resourceArn=db_cluster_arn,
database=database_name)
sql = 'INSERT INTO T_RIG_ACTIVITY_STATUS_DATE VALUES (:ID, :DRAW_WORKS);'
parameter_set = []
with open('test.csv', 'r') as file:
reader = csv.DictReader(file, delimiter=',')
for row in reader:
entry = [
{'name': 'ID','value': {'stringValue': row['RIG_ID']}},
{'name': 'DRAW_WORKS', 'value': {'longValue': row['DRAW_WORKS']}}
]
parameter_set.append(entry)
response = batch_execute_statement(
sql, parameter_set, transaction['transactionId'])
However, there is an error that gets returned suggests that there is a type mismatch:
Invalid type for parameter parameterSets[0][5].value.longValue,
value: NULL, type: <class 'str'>, valid types: <class 'int'>"
Is there a way to configure Aurora to accept NULL values for types such as int?

Answer 1

Reading the boto3 documentation more carefully I found that we can use isNull value set to True in case a field is NULL. The bellow code snippet shows how to insert null value to the database:
...
entry = [
{'name': 'ID','value': {'stringValue': row['ID']}}
]
if row['DRAW_WORKS'] == 'NULL':
entry.append({'name': 'DRAW_WORKS', 'value': {'isNull': True}})
else:
entry.append({'name': 'DRAW_WORKS_RATING', 'value': {'longValue': int(row['DRAW_WORKS'])}})
parameter_set.append(entry)