Why is this if else statement in python not working?

I have a program which adds array data to a database. I want to check and see if a record already exists. If the record already exists, then I don't want to add it to the array ( and eventually the database) . I created an if else statement to only add the data to the array if it doesn't already exist in the databse. However, when I check to see if the duplicate data is added in the database, I get

test=# select count(*) from cert;
count 
-------
100
(1 row)

test=# select count(*) from cert;
count 
-------
200
(1 row)

test=# 

the second hundred added are all duplicate entries

Here is my Python code where I am attempting to filter these duplicates out:

for i in range(0, length):
row_count = 0
idcheck = cleanse(json.dumps(fulljson[i]["id"]))
cur.execute("SELECT id from cert where id = %s;", [idcheck])
row_count = cur.rowcount
if row_count > 0:
  exists = True

else:
  exists = False

if not exists:

    column = 0
    #create a sub json variable for the "issuer" sub attributes
    issuerSubJson = json.dumps(fulljson[i]["issuer"]) 
    issuerSubJson2 = json.loads(issuerSubJson)

    id1 = cleanse(json.dumps(fulljson[i]["id"]))
    certgrab_array[i][column] = id1

    tbs_sha256 = cleanse(json.dumps(fulljson[i]["tbs_sha256"]))
    certgrab_array[i][1] = tbs_sha256

    dns = cleanse(json.dumps(fulljson[i]["dns_names"]))

    certgrab_array[i][2] = dns

    pubkey_sha256 = cleanse(json.dumps(fulljson[i]["pubkey_sha256"]))
    certgrab_array[i][3] = pubkey_sha256

    j = 4
    name = cleanse(json.dumps(issuerSubJson2["name"]))
    certgrab_array[i][j] = name
    j = j + 1
    issuerSha256 = cleanse(json.dumps(issuerSubJson2["pubkey_sha256"]))
    certgrab_array[i][j] = issuerSha256

    not_before = cleanse(json.dumps(fulljson[i]["not_before"]))
    certgrab_array[i][6] = not_before

    not_after = cleanse(json.dumps(fulljson[i]["not_after"]))
    certgrab_array[i][7] = not_after

    p = 8
  #Create a sub json variable for the "cert" sub attributes
    certSubJson = json.dumps(fulljson[i]["cert"])
    certSubJson2 = json.loads(certSubJson)

    certType = cleanse(json.dumps(certSubJson2["type"]))
    certgrab_array[i][p] = certType
    p = p + 1

    sha256 = cleanse(json.dumps(certSubJson2["sha256"]))
    certgrab_array[i][p] = sha256
    p = p + 1
    data = cleanse(json.dumps(certSubJson2["data"]))
    certgrab_array[i][p] = data
else:
    continue  


insert_query = "INSERT INTO cert(id, tbs_sha256, dns_names, pubkey_sha256, issuer_name, issuer_pubkey_sha256, not_before, not_after, cert_type, cert_hash, cert_data) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)"

cur.executemany(insert_query, certgrab_array)
conn.commit()

I have noticed the boolean gets its value as intended, but for whatever reason these values keep getting added. Also, the idcheck variable gets the intended value as well.