-------------------------------------------
lines 65-108 of file: xrst/all_node_db.xrst
-------------------------------------------

{xrst_begin omega_grid}

Omega Grid
##########
The :ref:`glossary@omega_grid` is specified by the
omega_age_grid and omega_time_grid tables.

omega_age_grid Table
********************
This table has two columns, *omega_age_grid_id* and age_id.
If this table is empty, the omega_time_grid table must also be empty.

n_omega_age
===========
We use the notation n_omega_age for the number of values in this table.

omega_age_grid_id
=================
is the :ref:`all_node_db@Primary Key` for this table.

age_id
======
This column has type ``integer`` and specifies the age grid points
by their index in the :ref:`glossary@root_database` age table.

omega_time_grid Table
*********************
This table has two columns, *omega_time_grid_id* and time_id.
If this table is empty, the omega_age_grid table must also be empty.

n_omega_time
============
We use the notation n_omega_time for the number of values in this table.

omega_time_grid_id
==================
is the :ref:`all_node_db@Primary Key` for this table.

time_id
=======
This column has type ``integer`` and specifies the time grid points
by their index in the root_database time table.

{xrst_end omega_grid}