def check_column_existence(dbHost, dbPort, dbName, dbUser, dbPassword, table_name, column_name):
    sqlQuery="""select count(*) from
INFORMATION_SCHEMA.columns
where table_name='{}' and column_name='{}';""".format(table_name, column_name)
    conn = pymssql.connect(host=dbHost, port=dbPort, user=dbUser, password=dbPassword, database=dbName)
    cursor = conn.cursor()
    sql = sqlQuery.encode('utf-8')
    cursor.execute(sql)
    for row in cursor:
        if row[0] == 1:
            result = True
        else:
            result = False
    print(result)
    return result

def populate_db_attribute_existence(dbHost, dbPort, dbName, dbUser, dbPassword, input_csv_file_path):
    input_csv_file_path = os.path.abspath(input_csv_file_path)
    input_csv_folder_path = os.path.dirname(input_csv_file_path)
    input_csv_file_name = os.path.basename(input_csv_file_path)
    temp1_output_file_path = "{}/temp1_{}".format(input_csv_folder_path, input_csv_file_name)
    temp2_output_file_path = "{}/temp2_{}".format(input_csv_folder_path, input_csv_file_name)

    df = pd.read_csv(input_csv_file_path)
    df['DB_Entity'] = df['DB_Entity'].str.replace(' ', '')
    df['DB_Attributes'] = df['DB_Attributes'].str.replace(' ', '')
    df2 = df[['API_Attributes', 'DB_Entity', 'DB_Attributes']]
    df2.to_csv(temp1_output_file_path, index=False, encoding='utf-8')

    with open(temp1_output_file_path,'r') as ftemp1, open(temp2_output_file_path,'w') as ftemp2:
        i = 1
        for row in ftemp1:
            if i > 1:
                row = row.strip()
                list_columns = row.split(',')
                api_attr_name = list_columns[0]
                db_entity_name = list_columns[1]
                c_name = list_columns[2]
                t_name = 'dbo.{}'.format(db_entity_name)
                result = check_column_existence(dbHost, dbPort, dbName, dbUser, dbPassword, t_name, c_name)
                ftemp2.write(','.join([api_attr_name, db_entity_name, c_name, str(result)])+'n')
            i += 1



    del(df2)
    df2 = pd.read_csv(temp2_output_file_path, names=['API_Attributes', 'DB_Entity', 'DB_Attributes', 'DB_Attr_Exist'])
    merge_key = ['API_Attributes', 'DB_Attributes']
    merged_df = pd.merge(df, df2, on=merge_key, how='outer')
    merged_df.to_csv(input_csv_file_path, index=False, encoding='utf-8')
    os.remove(temp1_output_file_path)
    os.remove(temp2_output_file_path)
    print("Completed DB Attributes existence check: {}".format(input_csv_file_path))