Abrufen von Datenbank-Metadaten

The parameter AddMetaDataForQueries (since X4 Server Revision 32408) enables to output database metadata to the respective result set in the result XML document, in common with the results of the SQL statement.

The name of each XML element containing the corresponding metadata consists of the resulttag attribute's value within the input document and the appendix -meta, e. g. <result-meta>.

For SQL statements that do not produce a result set (e. g. UPDATE or DELETE) no metadata can be output. When using the adapter's batch mode (StatementBatch, PreparedStatementBatch or CallableStatementBatch) this feature is neither available.

Example

The following input XML document defines an SQL query and a result element with the name result:

HTML/XML

<Root>
   <statement resulttag="result">
      <sql> SELECT X4USER, STARTTIME FROM HISTORY WHERE PID='1279017294476' </sql>
   </statement>
</Root>

Then, the JDBC Iterator outputs e. g. the following result XML document that contains the SQL query's results as well as the result set's metadata:

HTML/XML

<Data>
   <result-meta columns="2">
      <Column name="X4USER" label="X4USER" type="VARCHAR"
         nullable="true" auto-increment="false" read-only="false"
         writable="false" display-size="255" case-sensitive="true"
         searchable="true" signed="false" />
      <Column name="STARTTIME" label="STARTTIME" type="TIMESTAMP"
         nullable="true" auto-increment="false" read-only="false"
         writable="false" display-size="26" case-sensitive="false"
         searchable="true" signed="false" />
   </result-meta>
   <result>
      <X4USER>1</X4USER>
      <STARTTIME>2010-07-13 12:34:54.553</STARTTIME>
   </result>
</Data>