dbListTables: list materialized views as well, r-dbi#251

use pg_class/pg_namespace instead of information_schema.tables

Author: dpprdan

R/tables.R

@@ -236,9 +236,14 @@ setMethod("dbReadTable", c("PqConnection", "character"),
 #' @rdname postgres-tables
 setMethod("dbListTables", "PqConnection", function(conn, ...) {
   query <- paste0(
-    "SELECT table_name FROM INFORMATION_SCHEMA.tables ",
-    "WHERE ",
-    "(table_schema = ANY(current_schemas(true))) AND (table_schema <> 'pg_catalog')"
+    # pg_class docs: https://www.postgresql.org/docs/current/catalog-pg-class.html
+    "SELECT cl.relname AS name FROM pg_class AS cl ",
+    "JOIN pg_namespace AS n ON cl.relnamespace = n.oid ",
+    "WHERE (n.nspname = ANY (current_schemas(true))) ",
+    "AND (n.nspname <> 'pg_catalog') ",
+    "AND (cl.relkind IN ('r', 'p', 'f', 'v', 'm')) ",
+    "AND NOT cl.relispartition ",
+    "ORDER BY name"
   )
   dbGetQuery(conn, query)[[1]]
 })