diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index b0f6709aa..1c5d8fc9e 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -480,13 +480,20 @@ int LocalStore::getSchema()
 
 void LocalStore::openDB(State & state, bool create)
 {
+    if (create && readOnly) {
+        throw Error("unable to create database while in read-only mode");
+    }
+
     if (access(dbDir.c_str(), R_OK | (readOnly ? 0 : W_OK)))
         throw SysError("Nix database directory '%1%' is not writable", dbDir);
 
     /* Open the Nix database. */
     std::string dbPath = dbDir + "/db.sqlite";
     auto & db(state.db);
-    state.db = SQLite(dbPath, create);
+    auto openMode = readOnly ? SQLiteOpenMode::ReadOnly
+                  : create ? SQLiteOpenMode::Normal
+                  : SQLiteOpenMode::NoCreate;
+    state.db = SQLite(dbPath, openMode);
 
 #ifdef __CYGWIN__
     /* The cygwin version of sqlite3 has a patch which calls
diff --git a/src/libstore/sqlite.cc b/src/libstore/sqlite.cc
index df334c23c..8159744b7 100644
--- a/src/libstore/sqlite.cc
+++ b/src/libstore/sqlite.cc
@@ -50,14 +50,15 @@ static void traceSQL(void * x, const char * sql)
     notice("SQL<[%1%]>", sql);
 };
 
-SQLite::SQLite(const Path & path, bool create)
+SQLite::SQLite(const Path & path, SQLiteOpenMode mode)
 {
     // useSQLiteWAL also indicates what virtual file system we need.  Using
     // `unix-dotfile` is needed on NFS file systems and on Windows' Subsystem
     // for Linux (WSL) where useSQLiteWAL should be false by default.
     const char *vfs = settings.useSQLiteWAL ? 0 : "unix-dotfile";
-    int flags = SQLITE_OPEN_READWRITE;
-    if (create) flags |= SQLITE_OPEN_CREATE;
+    int flags = mode == SQLiteOpenMode::ReadOnly
+        ? SQLITE_OPEN_READONLY : SQLITE_OPEN_READWRITE;
+    if (mode == SQLiteOpenMode::Normal) flags |= SQLITE_OPEN_CREATE;
     int ret = sqlite3_open_v2(path.c_str(), &db, flags, vfs);
     if (ret != SQLITE_OK) {
         const char * err = sqlite3_errstr(ret);
diff --git a/src/libstore/sqlite.hh b/src/libstore/sqlite.hh
index 8f4bc49a8..33f0eeed8 100644
--- a/src/libstore/sqlite.hh
+++ b/src/libstore/sqlite.hh
@@ -36,7 +36,7 @@ struct SQLite
 {
     sqlite3 * db = 0;
     SQLite() { }
-    SQLite(const Path & path, bool create = true);
+    SQLite(const Path & path, SQLiteOpenMode mode = SQLiteOpenMode::Normal);
     SQLite(const SQLite & from) = delete;
     SQLite& operator = (const SQLite & from) = delete;
     SQLite& operator = (SQLite && from) { db = from.db; from.db = 0; return *this; }