diff --git a/src/Model/Migration.hs b/src/Model/Migration.hs
index d5f10dfcb..3328e0939 100644
--- a/src/Model/Migration.hs
+++ b/src/Model/Migration.hs
@@ -116,20 +116,36 @@ customMigrations = Map.fromListWith (>>)
         -- Read old table into memory
         -- schoolTable :: [(Single Int64, Single Text)]
         schoolTable <- [sqlQQ| SELECT "id", "shorthand" FROM "school"; |]
-        let _sT = schoolTable :: [(Single Int64, Single (CI Text))]
+        let _sT = schoolTable :: [(Single Int64, Single (CI Text))] -- Types needed
         -- Convert columns containing SchoolId
-        [executeQQ|
-            ALTER TABLE "user_admin"    ALTER COLUMN "school" TYPE citext;
-            ALTER TABLE "user_lecturer" ALTER COLUMN "school" TYPE citext;
-            ALTER TABLE "course"        ALTER COLUMN "school" TYPE citext;
-          |]
+        let convert0 = [executeQQ|
+                ALTER TABLE "user_admin"    DROP CONSTRAINT user_admin_school_fkey;
+                ALTER TABLE "user_lecturer" DROP CONSTRAINT user_lecturer_school_fkey;
+                ALTER TABLE "course"        DROP CONSTRAINT course_school_fkey;
+              |]
+        let convert1 = [executeQQ|
+                ALTER TABLE "user_admin"    ALTER COLUMN "school" TYPE citext USING to_char();
+                ALTER TABLE "user_lecturer" ALTER COLUMN "school" TYPE citext USING to_char();
+                ALTER TABLE "course"        ALTER COLUMN "school" TYPE citext USING to_char();
+              |]
         -- Convert Number-Strings to Shorthands
-        forM_ schoolTable (\(Single idnr, Single ssh) ->
-          [executeQQ|
-              UPDATE "user_admin"    SET "school" = '#{ssh}' WHERE "school" = '#{idnr}';
-              UPDATE "user_lecturer" SET "school" = '#{ssh}' WHERE "school" = '#{idnr}';
-              UPDATE "user_course"   SET "school" = '#{ssh}' WHERE "school" = '#{idnr}';
-            |]
-          )
+        let convert2 = forM_ schoolTable (\(Single idnr, Single ssh) ->
+                [executeQQ|
+                  UPDATE "user_admin"    SET "school" = #{ssh} WHERE "school" = #{idnr};
+                  UPDATE "user_lecturer" SET "school" = #{ssh} WHERE "school" = #{idnr};
+                  UPDATE "user_course"   SET "school" = #{ssh} WHERE "school" = #{idnr};
+                |]
+              )
+        -- Recreate constraints
+        let convert3 = [executeQQ|
+                ALTER TABLE "user_admin"    ADD CONSTRAINT "user_admin_school_fkey"
+                  FOREIGN KEY (school) REFERENCES school(shorthand);
+                ALTER TABLE "user_lecturer" ADD CONSTRAINT "user_lecturer_school_fkey"
+                  FOREIGN KEY (school) REFERENCES school(shorthand);;
+                ALTER TABLE "course"        ADD CONSTRAINT "course_school_fkey"
+                  FOREIGN KEY (school) REFERENCES school(shorthand);
+              |]
+        let convert = convert0 >> convert1 >> convert2 >> convert3
+        convert
     )
   ]