diff --git a/src/schema.sql b/src/schema.sql
index 65aebbd..bad2f6d 100644
--- a/src/schema.sql
+++ b/src/schema.sql
@@ -1,7 +1,7 @@
 BEGIN TRANSACTION;
 
 CREATE TABLE Specifications (
-  repo_name     TEXT NOT NULL PRIMARY KEY,
+  repo_name     TEXT NOT NULL,
   url           TEXT NOT NULL,
   load_path     TEXT NOT NULL,
   file          TEXT NOT NULL,
@@ -11,7 +11,8 @@ CREATE TABLE Specifications (
   branch        TEXT,
   tag           TEXT,
   revision      TEXT,
-  no_compile_p  INTEGER
+  no_compile_p  INTEGER,
+  PRIMARY KEY (repo_name, branch)
 );
 
 CREATE TABLE Stamps (