The pgtcl library has many ways of providing data. Here are some of them.
Examples of using the numerous options for pg_result (pg::result):
% set reshandle [pg_exec $connhandle "SELECT * FROM Pg_class LIMIT 5"]
Checking for query status:
% pg_result $reshandle -status PGRES_TUPLES_OK
Checking for query error:
% pg_result $reshandle -error
Getting the connection name:
% pg_result $reshandle -conn pgsql188
Getting the number of tuples in the result set:
% pg_result $reshandle -numTuples 5
Getting the number of attributes in the result set:
% pg_result $reshandle -numAttrs 24
-assign arrayName assigns the data to an array, which is indexed by the tuple number, and the column name, i.e. arrayName(0,column_name)
% pg_result $reshandle -assign resArray
% parray resArray
resArray(0,relacl) = {postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}
resArray(0,relam) = 0
resArray(0,relchecks) = 0
resArray(0,relfilenode) = 17100
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.
.
resArray(4,reltoastidxid) = 0
resArray(4,reltoastrelid) = 0
resArray(4,reltriggers) = 0
resArray(4,reltuples) = 0
resArray(4,reltype) = 17116
resArray(4,relukeys) = 0
% unset resArray-assignbyidx arrayName assigns the data to an array, which is indexed by the name of the first column, and the column name, i.e. arrayName(first_column,column_name).
% pg_result $reshandle -assignbyidx resArray
% parray resArray
resArray(table_constraints,relacl) = {postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}
resArray(table_constraints,relam) = 0
resArray(table_constraints,relchecks) = 0
resArray(table_constraints,relfilenode) = 17100
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resArray(triggers,relrefs) = 0
resArray(triggers,reltoastidxid) = 0
resArray(triggers,reltoastrelid) = 0
resArray(triggers,reltriggers) = 0
resArray(triggers,reltuples) = 0
resArray(triggers,reltype) = 17116
resArray(triggers,relukeys) = 0
% pg_result $reshandle -getTuple 0
table_constraints 16977 17101 1 0 17100 0 0 0 0 f f v 9 0 0 0 0 0 f f t f
{{postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}}
% unset resArray-tupleArray rowNumber arrayName assigns the data for one tuple (row), specified by rowNumber, to an array, which is indexed by the name of the column, i.e. arrayName(column_name).
% pg_result $reshandle -tupleArray 0 resArray
% parray resArray
resArray(relacl) = {postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}
resArray(relam) = 0
resArray(relchecks) = 0
resArray(relfilenode) = 17100
resArray(relfkeys) = 0
resArray(relhasindex) = f
resArray(relhasoids) = f
resArray(relhaspkey) = f
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resArray(reltoastidxid) = 0
resArray(reltoastrelid) = 0
resArray(reltriggers) = 0
resArray(reltuples) = 0
resArray(reltype) = 17101
resArray(relukeys) = 0
% pg_result $reshandle -attributes
relname relnamespace reltype relowner relam relfilenode relpages reltuples reltoastrelid reltoastidxid relhasindex
relisshared relkind relnatts relchecks reltriggers relukeys relfkeys relrefs relhasoids relhaspkey relhasrules
relhassubclass relacl
% pg_result $reshandle -lAttributes
{relname 19 64} {relnamespace 26 4} {reltype 26 4} {relowner 23 4} {relam 26 4} {relfilenode 26 4} {relpages 23 4}
{reltuples 700 4} {reltoastrelid 26 4} {reltoastidxid 26 4} {relhasindex 16 1} {relisshared 16 1} {relkind 18 1}
{relnatts 21 2} {relchecks 21 2} {reltriggers 21 2} {relukeys 21 2} {relfkeys 21 2} {relrefs 21 2} {relhasoids 16 1}
{relhaspkey 16 1} {relhasrules 16 1} {relhassubclass 16 1} {relacl 1034 -1}-list returns the data as one list. each column of each row are elements in the list
% set mylist [pg_result $reshandle -list]
table_constraints 16977 17101 1 0 17100 0 0 0 0 f f v 9 0 0 0 0 0 f f t f
{{postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}} table_privileges 16977 17105 1 0 17104 0 0 0 0 f f v 8 0 0 0 0 0 f f
t f {{postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}} tables 16977 17109 1 0 17108 0 0 0 0 f f v 9 0 0 0 0 0 f f t f
{{postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}} ...-llist option returns the data as a list of lists, where each element of the list represents each row in the results, and each sublist represents the columns for those rows.
% set mylist [pg_result $reshandle -llist]
{table_constraints 16977 17101 1 0 17100 0 0 0 0 f f v 9 0 0 0 0 0 f f t f
{{postgres=a*r*w*d*R*x*t*/postgres,=r/postgres}}} {table_privileges 16977 17105 1 0 17104 0 0 0 0 f f v 8 0 0 0 0 0 f
f t f ...-dict option returns the data in dictionary format, so that you can use the data as a dictionary. Note that you need dictionary support in Tcl (either Tcl 8.5 or the dict extension) in order to use this option
% set mydict [pg_result $reshandle -dict]
3 {relpages 1 relfkeys 0 relnatts 2 relhasoids f relhassubclass f relam 403 reltoastidxid 0 reltuples 0 relacl {}
relhaspkey f reltriggers 0 relname pg_toast_17173_index relrefs 0 reltype 0 relukeys 0 relchecks 0 relisshared f
reltablespace 0 reltoastrelid 0 relnamespace 99 relowner 1 relfilenode 17177 relkind i relhasrules f relhasindex f}
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% dict get $mydict 1
relpages 0 relfkeys 0 relnatts 5 relhasoids f relhassubclass f relam 0 reltoastidxid 0 reltuples 0 relacl ...
% % dict get $mydict 1 relname
data_type_privileges