Added convenience method and result fields when querying foreign keys in a Postg…

…res db. These fields provide the names of the referencing column and referenced table and column in the result similar to SQLite syntax.

lib/dialects/postgres/query.js

@@ -119,6 +119,18 @@ module.exports = (function() {
           delete result.columns;
           delete result.columns;
         });
         });
         return results;
         return results;
+      } else if (self.isForeignKeysQuery) {
+        result = [];
+        rows.forEach(function(row) {
+          var defParts;
+          if (row.condef !== undefined && (defParts = row.condef.match(/FOREIGN KEY \((.+){1}\) REFERENCES (.+){1}\((.+){1}\)/))) {
+            row.table = defParts[2];
+            row.from = defParts[1];
+            row.to = defParts[3];
+          }
+          result.push(row);
+        });
+        return result;
       } else if (self.isSelectQuery()) {
       } else if (self.isSelectQuery()) {
         if (self.sql.toLowerCase().indexOf('select c.column_name') === 0) {
         if (self.sql.toLowerCase().indexOf('select c.column_name') === 0) {
           result = {};
           result = {};
@@ -251,6 +263,10 @@ module.exports = (function() {
     return this.sql.indexOf('pg_get_indexdef') !== -1;
     return this.sql.indexOf('pg_get_indexdef') !== -1;
   };
   };
 
 
+  Query.prototype.isForeignKeysQuery = function() {
+    return this.sql.match(/SELECT conname as constraint_name, pg_catalog\.pg_get_constraintdef(r\.oid, true) as condef FROM pg_catalog\.pg_constraint r WHERE r\.conrelid = (SELECT oid FROM pg_class WHERE relname = '.*' LIMIT 1) AND r\.contype = 'f' ORDER BY 1;/g);
+  }
+
   Query.prototype.getInsertIdField = function() {
   Query.prototype.getInsertIdField = function() {
     return 'id';
     return 'id';
   };
   };