initial commit 2

domain/contract/data.go

@@ -0,0 +1,16 @@
+package contract
+
+// DataManager holds the methods that manipulates the main data.
+type DataManager interface {
+	repoManager
+	Begin() (TransactionManager, error)
+	Close() error
+}
+
+// TransactionManager holds the methods that manipulates the main
+// data, from within a transaction.
+type TransactionManager interface {
+	repoManager
+	Rollback() error
+	Commit() error
+}