Generate add/drop foreign key migration statements

Also add the --fkeys-deferrable-mode option. General schemas generation
rework.

1 files changed, 16 insertions, 0 deletions

diff --git a/odb/options.cli b/odb/options.cli
index 457c06f..569566d 100644
--- a/odb/options.cli
+++ b/odb/options.cli
@@ -169,6 +169,22 @@ class options
      schema name, is used."
   };
 
+  database_map<deferrable> --fkeys-deferrable-mode
+  {
+    "<m>",
+    "Use constraint checking mode <m> in foreign keys generated for object
+     relationships. Valid values for this option are \cb{not_deferrable},
+     \cb{immediate}, and \cb{deferred} (default). MySQL and SQL Server do
+     not support deferrable foreign keys and for these databases such keys
+     are generated commented out. Other foreign keys generated by the ODB
+     compiler (such as the ones used to support containers and polymorphic
+     hierarchies) are always generated as not deferrable.
+
+     Note also that if you use either \cb{not_deferrable} or \cb{immediate}
+     mode, then the order in which you persist, update, and erase objects
+     within a transaction becomes important."
+  };
+
   std::string --default-pointer = "*"
   {
     "<ptr>",