[dna-issues] [JBoss JIRA] Commented: (DNA-37) Federate schema information from relational sources

[ https://jira.jboss.org/jira/browse/DNA-37?page=com.atlassian.jira.plugin.... ] Sergiy Litsenko commented on DNA-37: ------------------------------------ I agree - we have plenty of work to do with database metadata integration with Connector on its own. But before I forgot I'm posting the following reference links that might be ususeful for future discussions/decisions about data paging and sampling (may be similar to Google (search for 'java' term returns "Results 1 - 10 of about 368,000,000 for java") it is related to several layers - not just the connector for relational sources: - JCR spec and our implementation, REST access / Atom publishing. package org.jboss.dna.graph.requests ReadBlockOfChildrenRequest startingIndex the index of the first child to be included in the block count the maximum number of children that should be included in the block ReadNextBlockOfChildrenRequest startingAfter the child that was the last child of the previous block of children read count the maximum number of children that should be included in the block 6.2.3 Node Read Methods public interface Node extends Item { NodeIterator getNodes(); // Returns all child nodes of this node. } public interface NodeIterator extends RangeIterator {} public interface RangeIterator extends Iterator { public long getSize(); // the number of elements in the iterator public long getPosition(); // current position within the iterator public void skip(long skipNum); // Skip a number of elements in the iterator } 6.6.12 Query Results javax.jcr.query.QueryResult: RowIterator getRows(); // query result as an iterator public interface RowIterator extends RangeIterator {} public interface Query { setMaxResults(int maxResult);// Set the maximum number of results to retrieve. setFirstResult(int startPosition) ; // Set the position of the first result to retrieve. } While feed paging is not directly supported by http://www.ietf.org/rfc/rfc4287.txt (correct me if I wrong) it might be useful implementing data paging using 'rel' attribute of the <link>element. Some example described here: http://www.ibm.com/developerworks/library/x-tipatom2/ "Paging Atom: Create a multi-section Atom collection or feed". See an example below for Atom + OpenSearch combined. From Open Search prospective (http://www.opensearch.org/Specifications/OpenSearch/1.1 and http://en.wikipedia.org/wiki/OpenSearch): OpenSearch 1.1 parameters: The "count" parameter - Replaced with the number of search results per page desired by the search client. The "startIndex" parameter - Replaced with the index of the first search result desired by the search client. The "startPage" parameter - Replaced with the page number of the set of search results desired by the search client. An example for Atom + OpenSearch combined: <feed xmlns="http://www.w3.org/2005/Atom" xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/"> <opensearch:Query role="request" searchTerms="JBoss DNA" startPage="1"/> <opensearch:totalResults>12345</opensearch:totalResults> <opensearch:startIndex>21</opensearch:startIndex> <opensearch:itemsPerPage>10</opensearch:itemsPerPage> <link rel="self" type="application/atom+xml" href="http://www.jboss.org/dna/atomFeed"/> <link rel="first" href="http://www.jboss.org/dna/atomFeed"/> <link rel="next" href="http://www.jboss.org/dna/atomFeed?page=2"/> <link rel="last" href="http://www.jboss.org/dna/atomFeed?page=123"/> <entry>...</entry> <entry>...</entry> </feed> -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: https://jira.jboss.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira