I have used pager taglib with sucess. Easy to use
Manuel Alzola
----- Original Message -----
From: "Jacob Hookom" <[EMAIL PROTECTED]>
To: "'OJB Users List'" <[EMAIL PROTECTED]>
Sent: Saturday, March 29, 2003 5:31 AM
Subject: RE: Webapp google queries: What is a good way to present multiple
web pages with query results ?
> I followed Scott's example and put one together for MySql, with setting up
> start index, end index with limit:
>
> public final class MySqlGenerator extends SqlGeneratorDefaultImpl
> {
> /**
> * @param arg0
> */
> public MySqlGenerator(Platform arg0)
> {
> super(arg0);
> }
>
> public String getPreparedSelectStatement(Query q, ClassDescriptor
> cd)
> {
> String result = super.getPreparedSelectStatement(q, cd);
> return this.addOffsetLimit(q, result);
> }
>
> public String getSelectStatementDep(Query q, ClassDescriptor cld)
> {
> String result = super.getSelectStatementDep(q, cld);
> return this.addOffsetLimit(q, result);
> }
>
> private String addOffsetLimit(Query q, String stmt)
> {
> int startIndex = q.getStartAtIndex();
> int endIndex = q.getEndAtIndex() - startIndex;
>
> if (endIndex <= 0)
> endIndex = -1;
>
> StringBuffer sb = new StringBuffer(stmt.length() + 16);
> sb.append(stmt);
> sb.append(" LIMIT ");
> sb.append(startIndex);
> sb.append(",");
> sb.append(endIndex);
>
> System.out.println(sb.toString());
> return sb.toString();
> }
> }
>
> | -----Original Message-----
> | From: Scott Howlett [mailto:[EMAIL PROTECTED]
> | Sent: Monday, March 24, 2003 10:28 AM
> | To: OJB Users List
> | Subject: RE: Webapp google queries: What is a good way to present
multiple
> | web pages with query results ?
> |
> | Mail list archive seems not to be working properly, otherwise I'd point
> | you to previous postings....
> |
> | 1. Use query.setStartAtIndex() and setEndAtIndex() to specify which
> | records you actually want to retrieve in the query.
> |
> | 2. Implement the functionality that translates these parameters into
> | something your database can understand by providing your own
> | SqlGenerator class and pointing to it OJB.properties.
> |
> | For example, I did it like this for PostgreSQL:
> |
> | My OJB.properties entry is:
> |
> | SqlGeneratorClass=PostgreSqlStatementGenerator
> |
> |
> | My subclass code is:
> |
> | import org.apache.ojb.broker.accesslayer.sql.SqlGeneratorDefaultImpl;
> | import org.apache.ojb.broker.metadata.ClassDescriptor;
> | import org.apache.ojb.broker.platforms.Platform;
> | import org.apache.ojb.broker.query.Query;
> |
> | public class PostgreSqlStatementGenerator extends
> | SqlGeneratorDefaultImpl {
> |
> | public SqlStatementGenerator(Platform pf) {
> | super(pf);
> | }
> |
> | public String getPreparedSelectStatement(
> | Query query,
> | ClassDescriptor cld) {
> | String result = super.getPreparedSelectStatement(query, cld);
> | return addOffsetLimit(query, result);
> | }
> |
> | public String getSelectStatementDep(Query query, ClassDescriptor
> | cld) {
> | String result = super.getSelectStatementDep(query, cld);
> | return addOffsetLimit(query, result);
> | }
> |
> | private String addOffsetLimit(Query q, String stmt) {
> | int startIndex = q.getStartAtIndex();
> | int endIndex = q.getEndAtIndex();
> | if (endIndex > 0) {
> | if (startIndex < 0 || startIndex >= endIndex) {
> | startIndex = 0;
> | }
> | stmt += " LIMIT " + (endIndex - startIndex);
> | }
> | if (startIndex > 0) {
> | stmt += " OFFSET " + startIndex;
> | }
> | return stmt;
> | }
> |
> | }
> |
> | Hope that helps,
> | Scott Howlett
> |
> |
> |
> | -----Original Message-----
> | From: Theo Niemeijer [mailto:[EMAIL PROTECTED]
> | Sent: Friday, March 21, 2003 5:08 AM
> | To: OJB Users List
> | Subject: Webapp google queries: What is a good way to present multiple
> | web pages with query results ?
> |
> |
> |
> | Maybe someone has a suggestion for me:
> |
> | The problem I am facing is that a user can have a very long list of
> | results, and that list of items is presented in multiple pages of HTML
> | (like Google :->)
> |
> | Let's assume that a query will have 10.000 resultitems, and I display 20
> | items per HTML page with a Next and a Previous button.
> |
> | - When I use a QueryIterator and for each next page just iterate 20
> | items further
> | I assume that it will tie the database connection up for quite some
> | time,
> | and I can not even be sure that the user will ask for the next page of
> | results !
> |
> | - When I just get all the items in a large collection it will cost me a
> | lot of "materialisation" time and a lot of memory.
> |
> | - When I only ask for the object identities and then get the pages by
> | making a query
> | for 20 identies in a kind of "select ... where id's in [....]" then the
> | user would have to wait for that query, but it may be mcuh faster than
> | the original query.
> |
> | - When I just re-submit the query for each page, and iterate to the
> | correct 20 items then the user would have to wait for the query each
> | time, but it may actually be fast because only 20 items would be
> | "materialised".
> |
> |
> | Anyone having experience with this problem and wanting to share best
> | practices ?
> |
> | Regards,
> | Theo Niemeijer
> |
> | ---------------------------------------------------------------------
> | To unsubscribe, e-mail: [EMAIL PROTECTED]
> | For additional commands, e-mail: [EMAIL PROTECTED]
> |
> |
> | ---------------------------------------------------------------------
> | To unsubscribe, e-mail: [EMAIL PROTECTED]
> | For additional commands, e-mail: [EMAIL PROTECTED]
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
