Search code examples
pythonpostgresqldataframepsycopg

copy dataframe to postgres table with column that has defalut value

I have the following postgreSql table stock, there the structure is following with column insert_time has a default value now()

|    column   |  pk |    type   |
+-------------+-----+-----------+
| id          | yes | int       |
| type        | yes | enum      |
| c_date      |     | date      |
| qty         |     | int       |
| insert_time |     | timestamp |

I was trying to copy the followning df

|  id | type |    date    | qty  |
+-----+------+------------+------+
| 001 | CB04 | 2015-01-01 |  700 |
| 155 | AB01 | 2015-01-01 |  500 |
| 300 | AB01 | 2015-01-01 | 1500 |

I was using psycopg to upload the df to the table stock

cur.copy_from(df, stock, null='', sep=',')
conn.commit()

getting this error. 

DataError: missing data for column "insert_time"
CONTEXT:  COPY stock, line 1: "001,CB04,2015-01-01,700"

I was expecting with the psycopg copy_from function, my postgresql table will auto-populate the rows along side the insert time.

|  id | type |    date    | qty  |     insert_time     |
+-----+------+------------+------+---------------------+
| 001 | CB04 | 2015-01-01 |  700 | 2018-07-25 12:00:00 |
| 155 | AB01 | 2015-01-01 |  500 | 2018-07-25 12:00:00 |
| 300 | AB01 | 2015-01-01 | 1500 | 2018-07-25 12:00:00 |
Solution

  • You can specify columns like this:

    cur.copy_from(df, stock, null='', sep=',', columns=('id', 'type', 'c_date', 'qty'))