pg_dump and boolean format

On Aug 11, 2010, at 13:00 , Scott Frankel wrote:

The pg docs say that booleans can be stored as 't', 'true', 'y', 'yes', or '1'.

Booleans are not "stored" as those literals: those are only acceptable literals (i.e., string representations) for boolean values.

I'm using pg_dump to create an SQL script for importing into another database. This will happen automatically and repeatedly. Unfortunately, the other database (sqlite) is limited to only integer representation of booleans: 0 or 1.

One option is to use COPY to export the data in a format you like. For example: COPY (SELECT CAST(boolean_column AS INT) FROM my_table) TO STDOUT. Then write a script which reads the exported data files and loads them into your sqlite database. COPY WITH CSV would likely be helpful as well.

Michael Glaesemann
grzm seespotcode net

On Aug 11, 2010, at 10:12 AM, Michael Glaesemann wrote:

On Aug 11, 2010, at 13:00 , Scott Frankel wrote:

The pg docs say that booleans can be stored as 't', 'true', 'y',
'yes', or '1'.

Booleans are not "stored" as those literals: those are only
acceptable literals (i.e., string representations) for boolean values.

Right.

I'm using pg_dump to create an SQL script for importing into
another database. This will happen automatically and repeatedly.
Unfortunately, the other database (sqlite) is limited to only
integer representation of booleans: 0 or 1.

One option is to use COPY to export the data in a format you like.
For example: COPY (SELECT CAST(boolean_column AS INT) FROM my_table)
TO STDOUT. Then write a script which reads the exported data files
and loads them into your sqlite database. COPY WITH CSV would likely
be helpful as well.

With the number of tables and insert statements I'll be wrangling, I
was hopeful I could coerce pg_dump to perform the "AS INT" cast.

Thanks for the tip!
Scott

On Aug 11, 2010, at 18:21 , Scott Frankel wrote:

On Aug 11, 2010, at 10:12 AM, Michael Glaesemann wrote:

One option is to use COPY to export the data in a format you like. For example: COPY (SELECT CAST(boolean_column AS INT) FROM my_table) TO STDOUT. Then write a script which reads the exported data files and loads them into your sqlite database. COPY WITH CSV would likely be helpful as well.

With the number of tables and insert statements I'll be wrangling, I was hopeful I could coerce pg_dump to perform the "AS INT" cast.

Query the database Information Schema or system tables to provide a list of the table names. By using COPY WITH CSV HEADER and the names of the tables, you should be able to generate INSERT statements programatically.

Michael Glaesemann
grzm seespotcode net

On Aug 11, 2010, at 3:57 PM, Michael Glaesemann wrote:

On Aug 11, 2010, at 18:21 , Scott Frankel wrote:

On Aug 11, 2010, at 10:12 AM, Michael Glaesemann wrote:

One option is to use COPY to export the data in a format you like.
For example: COPY (SELECT CAST(boolean_column AS INT) FROM
my_table) TO STDOUT. Then write a script which reads the exported
data files and loads them into your sqlite database. COPY WITH CSV
would likely be helpful as well.

With the number of tables and insert statements I'll be wrangling,
I was hopeful I could coerce pg_dump to perform the "AS INT" cast.

Query the database Information Schema or system tables to provide a
list of the table names. By using COPY WITH CSV HEADER and the names
of the tables, you should be able to generate INSERT statements
programatically.

Good point. Thanks for the suggestions!
Scott