Metadata
========
A series of simple examples are provided showing how to retrieve metadata about each database or table.


Database Listing
################

The list of Databases can be retrieved through the following SQL query.
The ``SYMBOL_NAME`` where clause needs to be specified.

.. code-block:: sql
   :caption: Database Listing

   select * from OTQ_CHAIN."SHOW_DB_LIST"
   where SYMBOL_NAME = 'DB_INFO::'



Database Authorized Listing
###########################

The list of authorised Databases, including restrictions around time ranges can be retrieved through the following SQL query.
The ``SYMBOL_NAME`` where clause needs to be specified.

.. code-block:: sql
   :caption: Database Authorised Listing

   SELECT * FROM OTQ_CHAIN."ACCESS_INFO(INFO_TYPE='DATABASES')"
   where SYMBOL_NAME = 'DB_INFO::'


Database Symbol Listing
#######################

Databases are partitioned by symbol, and must be queried by ``SYMBOL_NAME``.
The list of available symbols for a specified database can change by day, so the query must specify in the ``WHERE`` clause

* The Database as the ``SYMBOL_NAME`` field, suffixed with ``::``
* The Time window with the ``TIMESTAMP`` field.

.. code-block:: sql
   :caption: Symbol Listing for Specified Database and Time Window

   SELECT * FROM OTQ_CHAIN."FIND_DB_SYMBOLS(PATTERN='%')"
   where SYMBOL_NAME = 'LSE_SAMPLE::'
   and TIMESTAMP >= '2024-01-03 00:00:00 UTC'
   and TIMESTAMP < '2024-01-04 00:00:00 UTC'


Table Listing
#############

The list of tables for a specified database can be retrieved through the following SQL query.
The Database as the ``SYMBOL_NAME`` field, suffixed with ``::``

.. code-block:: sql
   :caption: Table Listing for Specified Database 

   select * from OTQ_CHAIN."DB/SHOW_TICK_TYPES"
   where SYMBOL_NAME = 'LSE_SAMPLE::'


Field Listing
#############

The list of fields for a specified database can be retrieved through the following SQL query.  
Each Symbol may potentially have a different schema so the symbol should also be specified along with the database.

* The Database and symbol as the ``SYMBOL_NAME`` field
* The Table after ``SHOW_TICK_DESCRIPTOR;``


.. code-block:: sql
   :caption: Field Listing for Specified Database, Symbol and Table

   SELECT * FROM OTQ_CHAIN."SHOW_TICK_DESCRIPTOR;TRD"
   where SYMBOL_NAME = 'LSE_SAMPLE::VOD'