Thread: How to obtain the max length of a varchar(50) field.
Hi all. I'm working with Postgres 9.0 and wxWidgets. I need to query the db about a field of a table. The table T has a field varchar(50). table: TAB0 customer: varchar(50) How can I get the max size of the field? The PQfsize function give me -1 because the field has dynamic size. Can you help me? Best regards MZ.
On Thu, May 5, 2011 at 9:50 AM, Mauro Ziliani <mauro@faresoftware.it> wrote: > Hi all. > I'm working with Postgres 9.0 and wxWidgets. > I need to query the db about a field of a table. > > The table T has a field varchar(50). > > table: TAB0 > customer: varchar(50) > > How can I get the max size of the field? > > The PQfsize function give me -1 because the field has dynamic size. > > Can you help me? Try PQfmod() -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
Mauro Ziliani <mauro@faresoftware.it> wrote: > Hi all. > I'm working with Postgres 9.0 and wxWidgets. > I need to query the db about a field of a table. > > The table T has a field varchar(50). > > table: TAB0 > customer: varchar(50) > > How can I get the max size of the field? select max(length(customer)) from tab0; Andreas -- Really, I'm not out to destroy Microsoft. That will just be a completely unintentional side effect. (Linus Torvalds) "If I was god, I would recompile penguin with --enable-fly." (unknown) Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889°
On 05/05/2011 11:03, Simon Riggs wrote: > On Thu, May 5, 2011 at 9:50 AM, Mauro Ziliani<mauro@faresoftware.it> wrote: >> Hi all. >> I'm working with Postgres 9.0 and wxWidgets. >> I need to query the db about a field of a table. >> >> The table T has a field varchar(50). >> >> table: TAB0 >> customer: varchar(50) >> >> How can I get the max size of the field? >> >> The PQfsize function give me -1 because the field has dynamic size. >> >> Can you help me? > Try PQfmod() > Ok I'll try it. Reading I skip this function. Thank you. MZ
On 05/05/2011 11:03, Andreas Kretschmer wrote: > Mauro Ziliani<mauro@faresoftware.it> wrote: > >> Hi all. >> I'm working with Postgres 9.0 and wxWidgets. >> I need to query the db about a field of a table. >> >> The table T has a field varchar(50). >> >> table: TAB0 >> customer: varchar(50) >> >> How can I get the max size of the field? > select max(length(customer)) from tab0; > > > > Andreas Thank you for the suggestion. But I look a C function which access PGresult record. This is usefull for an sql script. Thank you very much. MZ