Getting Table and Column names in PyOdbc

Question

I’d like to retrieve the fully referenced column name from a PyOdbc Cursor. For example, say I have 2 simple tables:

Table_1(Id, < some other fields >)
Table_2(Id, < some other fields >)

and I want to retrieve the joined data

select * from Table_1 t1, Table2 t2 where t1.Id = t2.Id

using pyodbc, like this:

query = 'select * from Table_1 t1, Table2 t2 where t1.Id = t2.Id'

import pyodbc
conn_string = '<removed>'
connection =  pyodbc.connect(conn_string)

cursor = connection.cursor()cursor.execute(query)

I then want to get the column names:

for row in cursor.description:
    print row[0]

BUT if I do this I’ll get Id twice which I don’t want. Ideally I could get t1.Id and t2.Id in the output.

Some of the solutions I’ve thought of (and why I don’t really want to implement them):

re-name the columns in the query – in my real-world use case there are dozens of tables, some with dozens of rows that are changed far too often
parse my query and automate my SQL query generation (basically checking the query for tables, using the cursor.tables function to get the columns and then replacing the select * with a set of named columns) – If I have too I’ll do this, but it seems like overkill for a testing harness

Is there a better way? Any advice would be appreciated.

Asked By: Brad

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Source

Answer 1

The PyOdbc docs offer

# columns in table x
for row in cursor.columns(table='x'):
    print(row.column_name)

www.PyOdbc wiki The API docs are useful

Answered By: Geordie Jon

Answer 2

It doesn’t seem to be possible to do what I want without writing a decent amount of code to wrap it up. None of the other answers actually answered the question of returning different column names by the table they originate from in some relatively automatic fashion.

Answered By: Brad

Answer 3

Here’s how I do it.

import pyodbc
connection = pyodbc.connect('DSN=vertica_standby', UID='my_user', PWD='my_password', ansi=True)
cursor = connection.cursor()
for row in cursor.columns(table='table_name_in_your_database'):
    print(row.column_name)

You have to have your DSN (data source name) set up via two files. odbc.ini and odbcinst.ini

Answered By: Russell Lego

Answer 4

seems like you want to alias your columns in the typical SQL fashion (inside the query string).
this link seems helpful for aliasing:
https://learnsql.com/blog/how-to-use-aliases-with-sql-join/

Then run your query with the cursor object, and from the result get the field names by: fields=[x[0] for x in cursor.description]

cursor docs:
https://code.google.com/archive/p/pyodbc/wikis/Cursor.wiki

Answered By: rhanzlick

Getting Table and Column names in PyOdbc

Question:

Answers:

The PyOdbc docs offer