Adding some early foreign key system.

1 files changed, 40 insertions, 8 deletions

diff --git a/lib/dblib.lua b/lib/dblib.lua
index 0c07edd..ffd93e6 100644
--- a/lib/dblib.lua
+++ b/lib/dblib.lua
@@ -459,7 +459,7 @@ _luadb = {
         return t._.db._.conn:NumAffectedRows()
     end,
     
-    iselect = function(t, fields, bypass)
+    iselect = function(bypass, t, fields, foreign, options)
         local stmt = "SELECT "
         local first = true
         local k, v
@@ -468,7 +468,16 @@ _luadb = {
             stmt = stmt .. "*"
         else        
             for k, v in pairs(fields) do
-                if not bypass and not t._.ddl[v] then
+                local is_foreign = false
+                if foreign then
+                    local _, f
+                    for _, f in pairs(foreign) do
+                        if f._.ddl[v] then
+                            is_foreign = true
+                        end
+                    end
+                end
+                if not bypass and not is_foreign and not t._.ddl[v] then
                     error("Trying to select a field which doesn't exist: " .. k .. " - inside of table " .. t._.tablename)
                 end
                 if not first then
@@ -484,7 +493,30 @@ _luadb = {
             end
         end
         
-        stmt = stmt .. " FROM " .. t._.tname .. " WHERE " .. t._.conditions
+        if foreign then
+            local foreign_conds = "1"
+            stmt = stmt .. " FROM " .. t._.tname
+            local found_table, fname, f
+            for k, v in foreign do
+                stmt = stmt .. ", " .. v._.tname
+                found_table = false
+                for fname, f in pairs(t._.ddl) do
+                    if f.foreign and f.foreign.tablename == v._.tablename then
+                        if not v._.ddl[f.foreign.fieldname] then
+                            error("Foreign key points to an unknown field in table: " .. f.foreign.tablename .. "." .. f.foreign.fieldname)
+                        end
+                        foreign_conds = foreign_conds .. " AND " .. t._.tname .. ".`" .. fname .. "`=" .. v._.tname .. ".`" .. f.foreign.fieldname .. "`"
+                        found_table = true
+                    end
+                end
+                if not found_table then
+                    error("Foreign table " .. v._.tablename .. " specified in request didn't match any of the foreign key of table " .. t._.tablename)
+                end
+            end
+            stmt = stmt .. " WHERE (" .. t._.conditions .. ") AND (" .. foreign_conds .. ")"
+        else
+            stmt = stmt .. " FROM " .. t._.tname .. " WHERE " .. t._.conditions
+        end
         
         if t._.db:SafeQuery(stmt) ~= 0 then
             error("Error selecting row(s) inside table " .. t._.tablename .. ": " .. t._.db:Error())
@@ -499,8 +531,8 @@ _luadb = {
         end
     end,
     
-    select = function(t, fields)
-        return _luadb.iselect(t, fields)
+    select = function(...)
+        return _luadb.iselect(false, ...)
     end,
     
     numrows = function(t)
@@ -512,12 +544,12 @@ _luadb = {
     end,
     
     count = function(t)
-	_luadb.iselect(t, {"COUNT(*) AS count"}, true)
+	_luadb.iselect(true, t, {"COUNT(*) AS count"})
 	return t:nextrow().count
     end,
     
-    gselect = function(t, fields)
-	_luadb.iselect(t, fields)
+    gselect = function(t, ...)
+	_luadb.iselect(false, t, ...)
         return t.nextrow, t
     end,