It is possible to use the OpenACS Tcl database API with other databases. In this example, the OpenACS site uses a PostgreSQL database, and accesses another PostgreSQL database called legacy.
Modify config.tcl to accommodate the legacy database, and to ensure that the legacy database is not used for standard OpenACS queries:
ns_section ns/db/pools ns_param pool1 "Pool 1" ns_param pool2 "Pool 2" ns_param pool3 "Pool 3" ns_param legacy "Legacy" ns_section ns/db/pool/pool1 #Unchanged from default ns_param maxidle 1000000000 ns_param maxopen 1000000000 ns_param connections 5 ns_param verbose $debug ns_param extendedtableinfo true ns_param logsqlerrors $debug if { $database eq "oracle" } { ns_param driver ora8 ns_param datasource {} ns_param user $db_name ns_param password $db_password } else { ns_param driver postgres ns_param datasource ${db_host}:${db_port}:${db_name} ns_param user $db_user ns_param password "" } ns_section ns/db/pool/pool2 #Unchanged from default, removed for clarity ns_section ns/db/pool/pool3 #Unchanged from default, removed for clarity ns_section ns/db/pool/legacy ns_param maxidle 1000000000 ns_param maxopen 1000000000 ns_param connections 5 ns_param verbose $debug ns_param extendedtableinfo true ns_param logsqlerrors $debug ns_param driver postgres ns_param datasource ${db_host}:${db_port}:legacy_db ns_param user legacy_user ns_param password legacy_password ns_section ns/server/${server}/db ns_param pools * ns_param defaultpool pool1 ns_section ns/server/${server}/acs/database ns_param database_names [list main legacy] ns_param pools_main [list pool1 pool2 pool3] ns_param pools_legacy [list legacy]
To use the legacy database, use the -dbn flag for any of the db_ API calls. For example, suppose there is a table
called "foo" in the legacy system, with a field
"bar". List "bar" for all records with this Tcl
file:
db_foreach -dbn legacy get_bar_query {
select bar from foo
limit 10
} {
ns_write "<br/>$bar"
}