+
−<p>
+
−  Exploring an LTPDA repository is most easily achieved using the purpose-built graphical user interface. This
+
−  interace is accesible either from the LTPDA workbench, or via a toolbar button the workspace browser.
+
−</p>
+
−<p>
+
−  The figure belows shows the query dialog that appears through either interface:
+
−  <br>
+
−  <img src="images/querydialog.png" alt="LTPDA Query Builder" border="3">
+
−  <br>
+
−</p>
+
−<p>
+
−  You can construct a query by use of the drop-down menus and buttons, then execute
+
−  the query to retreive a table of results, like the one shown below:
+
−  <br>
+
−  <img src="images/queryresults.png" alt="LTPDA Query Results" border="3">
+
−  <br>
+
−</p>
+
−<p>
+
−  If the query dialog is launched from within the LTPDA Workbench, the results table has an
+
−  additional button which can be used to create constructor blocks on the current pipeline
+
−  corresponding to the selected records in the results table.
+
−</p>
+
−
+
−
+
−<!--
+
−<p>
+
−  Since an LTPDA repository is just a MySQL database, you can query the database using standard
+
−  SQL commands via any of the popular MySQL clients. In addition, the LTPDA toolbox provides a 
+
−  simplified command that can be used to execute simple queries with only basic SQL knowledge.
+
−</p>
+
−<p>
+
−  The command is <tt>utils.mysql.dbquery</tt> and it can be used to perform various queries.
+
−  It takes the following input arguments:
+
−  <table border="1" cellpadding="2" width="30%" bgcolor="#DDDDDD">
+
−    <tr valign="top">
+
−      <td><tt>conn</tt></td><td>A database connection object</td>
+
−    </tr>
+
−    <tr valign="top">
+
−      <td><tt>tablename</tt></td><td>The name of a table to search</td>
+
−    </tr>
+
−    <tr valign="top">
+
−      <td><tt>query</tt></td><td>The query string written in MySQL SQL syntax</td>
+
−    </tr>
+
−  </table>	 
+
−  <br>
+
−Examples of usage are:
+
−
+
−</p>
+
−   
+
−<h2>Searching particular tables</h2>
+
− 
+
−<p> 
+
−  <div class="fragment"><pre>
+
−      >> info  = utils.mysql.dbquery(conn, 'select * from objmeta where id>1000 and id<2000');
+
−      >> info  = utils.mysql.dbquery(conn, 'ao',           'id>1000 and id<2000');
+
−      >> info  = utils.mysql.dbquery_dbquery(conn, 'objmeta',      'name like "x12"');
+
−      >> info  = utils.mysql.dbquery(conn, 'users',        'username="aouser"');
+
−      >> info  = utils.mysql.dbquery(conn, 'collections',  'id=3');
+
−      >> info  = utils.mysql.dbquery(conn, 'collections',  'obj_ids="1,2"');
+
−      >> info  = utils.mysql.dbquery(conn, 'transactions', 'user_id=3');
+
−      >> info  = utils.mysql.dbquery(conn, 'transactions', 'obj_id=56');
+
−  </pre></div>
+
−</p>
+
− 
+
−<h2>Retrieving a list of tables</h2>
+
− 
+
−<p> 
+
−  You can retrieve a list of the tables in a database with the call:
+
−  <div class="fragment"><pre>
+
−      >> info  = utils.mysql.dbquery(conn)
+
−  </pre></div>
+
−  
+
−</p>
+
−
+
−  
+
−<h2>High-level queries</h2>
+
−<p>
+
−  Various standard queries are envisaged which ask typical questions, such as:
+
−  "Give me data for a particular signal spanning a particular time-span".  
+
−</p>
+
−<p>
+
−  Formulating this question as an SQL query requires a good knowledge of the SQL
+
−  syntax used by MySQL. The query has to search across multiple tables in order
+
−  to gather the IDs of the objects that fulfill the query. For these standard questions,
+
−  high-level functions will be built which perform the query given some input information. This
+
−  avoids the user having to formulate complicated SQL statements.
+
−</p>
+
−<p>
+
−  The following high-level queries currently exist in the toolbox:
+
−<table border="1" cellpadding="2" bgcolor="#DDDDDD">
+
−  <tr valign="top">
+
−    <td><tt>ltpda_getAOsInTimeSpan</tt></td><td>Retrieve particular AOs in the given time-span</td>
+
−  </tr>
+
−</table>
+
−</p>
+
−
+
−-->