Use an application id and user version number for schema.

pkgin.sql

@@ -195,3 +195,6 @@ CREATE INDEX [idx_local_pkg_comment] ON [LOCAL_PKG] (
 CREATE INDEX [idx_local_pkg_name] ON [LOCAL_PKG] (
 	[PKGNAME] ASC
 );
+
+PRAGMA application_id = 1886087022;
+PRAGMA user_version = 1;

pkgindb.c

@@ -233,6 +233,31 @@ pkgindb_savepoint_release(uint64_t savepoint)
 	}
 }
 
+/*
+ * Check the application_id and user_version parameters.
+ */
+static int
+check_appid(void *param, int argc, char **argv, char **colname)
+{
+
+	if (argc != 1 || argv == NULL)
+		return PDB_ERR;
+	if (strcmp(argv[0], "1886087022") != 0)
+		return PDB_ERR;
+	return PDB_OK;
+}
+
+static int
+check_version(void *param, int argc, char **argv, char **colname)
+{
+
+	if (argc != 1 || argv == NULL)
+		return PDB_ERR;
+	if (strcmp(argv[0], "1") != 0)
+		return PDB_ERR;
+	return PDB_OK;
+}
+
 /*
  * Configure the pkgin database.  Returns 0 if opening an existing compatible
  * database, or 1 if the database needs to be created or recreated (in the case
@@ -277,7 +302,14 @@ pkgindb_open(void)
 			errx(EXIT_FAILURE, "cannot create database: %s",
 			    sqlite3_errmsg(pdb));
 	} else {
-		if (pkgindb_doquery(CHECK_DB_LATEST, NULL, NULL) != PDB_OK) {
+		if (pkgindb_doquery("PRAGMA application_id", check_appid, NULL)
+		    != PDB_OK) {
+			if (unlink(pkgin_sqldb) < 0)
+				err(EXIT_FAILURE, "cannot recreate database");
+			goto recreate;
+		}
+		if (pkgindb_doquery("PRAGMA user_version", check_version, NULL)
+		    != PDB_OK) {
 			if (unlink(pkgin_sqldb) < 0)
 				err(EXIT_FAILURE, "cannot recreate database");
 			goto recreate;

pkgindb_queries.c

@@ -27,17 +27,6 @@
  * SUCH DAMAGE.
  */
 
-/*
- * This query checks the compatibility of the current database, and should be
- * one that either completes or fails due to an SQL error based on the most
- * recent schema change.  Returned rows are ignored, so choose a query that
- * runs quickly.
- */
-const char CHECK_DB_LATEST[] =
-	"SELECT pkgbase "
-	"  FROM local_conflicts "
-	" LIMIT 1;";
-
 const char DELETE_LOCAL[] =
 	"DELETE FROM LOCAL_PKG;"
 	"DELETE FROM LOCAL_CONFLICTS;"