Thread: extracting constraints from schema

Hi,

I was just wondering whether you happen to know how to extract what the
table and column constraints are using jdbc?
The API provides methods for extracting meta data on the table names,
column names, primary and foreigh keys as well as column types and sizes.
What about extracting constraints such as

salary    real    CHECK (salary >= 10000)

?
It is possible to obtain the column name 'salary' as well as its types as
being 'real' but how about the CHECK condition?? Can it be done using
jdbc?

Thanks for your time and help
Agnes

Agnieszka Rutkowska wrote:
> Hi,
> 
> I was just wondering whether you happen to know how to extract what the
> table and column constraints are using jdbc?
> The API provides methods for extracting meta data on the table names,
> column names, primary and foreigh keys as well as column types and sizes.
> What about extracting constraints such as
> 
> salary    real    CHECK (salary >= 10000)
> 
> ?
> It is possible to obtain the column name 'salary' as well as its types as
> being 'real' but how about the CHECK condition?? Can it be done using
> jdbc?
> 
> Thanks for your time and help
> Agnes

Did you try to extract any information from system table pg_constraint?
contype='C' is a CHECK condition. I think you can parse some additional
information from column consrc. Description of all columns in this table
is in "Chapter 3. System Catalogs 10. pg_constraint" at Postgresql documentation.

Regards,
Tomasz Myrta