title: zend2: Oracle11g: Exception while retrieving columnNames from Metadata class
body: <p>iam using zendFramework2.5.1 with Oracle 11g. Database connectivity/DML queries executing fine.<br><br>
  i need to export the column names of a table present in oracleDB. i use <b>Zend\Db\TableGateway\TableGateway</b> for DB connectivity. i learnt that by using <b>Zend\Db\Metadata\Metadata</b> column names could be retrived. Using the $tableObject (as shown below), i retrieved the existing adapter object and table name. No issues here.</p>
  <pre><code>$metadataObject = new Metadata($tableObject-&gt;getAdapter());
  $tableName = $tableObject-&gt;getTable();
  </code></pre>
  <p>But when below code executes, exception occurs.</p>
  <pre><code>$metadataTable = $metadataObject-&gt;getTable($tableName); 
  </code></pre>
  <p><b>Exception</b></p>
  <pre><code>Zend\Db\Adapter\Exception\RuntimeException
  
  File:
  C:\wamp\www\zfc2\vendor\zendframework\zend-db\src\Adapter\Driver\Oci8\Statement.php:260
  Message:
  ORA-01745: invalid host/bind variable name
  Stack trace:
  #0 C:\wamp\www\zfc2\vendor\zendframework\zend-db\src\Metadata\Source\OracleMetadata.php(137):    Zend\Db\Adapter\Driver\Oci8\Statement-&gt;execute(Array)
  #1 C:\wamp\www\zfc2\vendor\zendframework\zend-db\src\Metadata\Source\AbstractSource.php(316): Zend\Db\Metadata\Source\OracleMetadata-&gt;loadConstraintData('CSS_MILIBRIS_US...', 'LNK1DB')
  #2 C:\wamp\www\zfc2\vendor\zendframework\zend-db\src\Metadata\Source\AbstractSource.php(142): Zend\Db\Metadata\Source\AbstractSource-&gt;getConstraints('CSS_MILIBRIS_US...', 'LNK1DB')
  #3 C:\wamp\www\zfc2\vendor\zendframework\zend-db\src\Metadata\Metadata.php(178): Zend\Db\Metadata\Source\AbstractSource-&gt;getTable('CSS_MILIBRIS_US...', NULL)
  #4 C:\wamp\www\zfc2\module\Kiosque\src\Kiosque\Controller\LandingController.php(76): Zend\Db\Metadata\Metadata-&gt;getTable('CSS_MILIBRIS_US...')
  #5 C:\wamp\www\zfc2\vendor\zendframework\zend-mvc\src\Controller\AbstractActionController.php(82):
  </code></pre>
  <p>i referred the  <a href="http://framework.zend.com/manual/current/en/modules/zend.db.metadata.html" rel="nofollow noreferrer">ZendDBManual Link</a>. and tried the same. i analyzed the exception,but couldn't proceed further with what i have analyzed.<br> What i observed going through websites is, this has something to do with accessing restricted variables present in oracle (am not sure about it).
  . Any help in providing solution for this issue is much appreciated.</p>