Greyhead.net. How-to docs and tutorials. ChronoConnectivity How-to doc Static filters for your listing CHRONO. Connectivity

Transcription

1 How-to docs and tutorials ChronoConnectivity How-to doc Static filters for your listing How to select the records to be displayed in ChronoConnection listing. Using the WHERE SQL box to select records Using the Order fields box to sort records Level: introductory, a little MySQL used. CHRONO Connectivity

2 Basic filters for your listing So far we ve seen how to create a list and format it. In this document we ll start to explore how to select and sort the records that are displayed. This processes of filtering and sorting the records from the database table can become quite complex so this is just an first introduction to the basic principles. In this document we'll just look at Static filters which you define in the listing setup. Getting ready: Before we get much further we need some records to sort and filter. Rather than take time to add more records to the Newsletter Signup table we used in the previous documents we'll use the Joomla! table that is used to store the articles instead. In the database this is called jos_content (though the prefix may be different if you have a custom setting on your Joomla! site). We need to create a new Connection linked to this table. Use exactly the same code in the Header, Body and Footer boxes as we had in the Newsletter Signup connection but change the Body columns we use to {title} and {hits}; and make the corresponding changes to the Listing Title and the Header box code. Remember also to make the minimum necessary settings on the Front End and Admin Settings tabs. (The code I used to create the listing is shown at the end of this document.) 1 Basic filters for your listing

3 Here s the listing that this creates. Notice that we have about 50 results (11 pages of 5) and that there is no particular order to the records. 2 Basic filters for your listing

4 ChronoConnectivity has one filtering box called WHERE SQL ; and one sorting box called Order fields. Behind the scenes each of these adds a extra clause to the MySQL query that will be used to get records from the database table. They both work in more or less the same way but the sorting box is simpler so we ll look at that first. Sorting records An entry in the sorting box will look like this: `column_name_1`, `column_name_2` ASC Do make sure that you have spelt the column names correctly or the listing may fail. Do not include the ORDER BY at the beginning of the list even though the ToolTip suggest that you should The Sort Direction defaults to ASC (ascending); use DESC (descending) to reverse the order. XXIf you aren t sure exactly what the column names are in the table you can see a list in the select box on the Admin Settings tab. You can add any number of column names separated by commas, though in practice I ve rarely used more than one or two. In our article listing we ll try `title` DESC 3 Basic filters for your listing

5 You can see that the list is now in reverse alphabetical order of the article titles. XXThe column that you use to sort by doesn t have to be visible in the listing; you can use any column name(s) in the table. Check the MySQL documents for more info. X X Unfortunately the current release of ChronoConnectivity doesn t have a box that will take a GROUP BY clause. It is possible but only by hacking the code. 4 Basic filters for your listing

6 Filtering records We use the WHERE SQL to filter records. Let s just select all the articles with more than 50 hits (choose a bigger number if your site is busy). The code to use is: WHERE `hits` > 50 I ve also used `hits` ASC in the Order Fields box so that we can see the list starts at 50 hits or more. 5 Basic filters for your listing

7 XXUnlike the Order Fields box we must include the WHERE in this box. It s just a quirk of the way the code is written but easy to overlook in one box or the other. We can use the WHERE MySQL box for more complex queries. Here s one example: WHERE `hits` > 20 AND `state` > 0 AND `title` LIKE '%Joomla%' XXThis will select all published articles with more than twenty hits where the name includes Joomla. X X Please refer to the MySQL documentation for the full syntax of the MySQL WHERE clause. 6 Basic filters for your listing

8 These two boxes will allow you to set up basic filtering and sorting of your records. However, the real strength of ChronoConnectivity is in creating Dynamic filters where the user is able to select records using a filter form. More about that in the next tutorial. XXIt is possible to create create column headers in ChronoConenctivity that will sort the records when the column header is clicked. However, this requires a small hack to the ChronoConnectivity code. The process is explained in the Sortable Columns How-to document. Bob Janes 12 September Basic filters for your listing

9 The Articles Listing code Here is the complete code for the listing that I created at the beginning of this document. Name: articles TableName(s): jos_content Header <?php $style = ""; $style.= " table.cf_listing { margin-bottom: 12px; } "; if ( $style) { $doc =& JFactory::getDocument(); $doc->addstyledeclaration($style); }?> <table class='cf_listing'> <thead> <tr> <th>title</th><th>hits</th> </tr> </thead> <tfoot> <tr> 8 Basic filters for your listing

10 Body Footer <td colspan='2' style='height:4px; background:silver;'></td> </tr> </tfoot> <tbody> <tr><td>{title}</td><td>{hits}</td></tr> </tbody> </table> {pagination} Header/Title: Joomla! Articles Enable Form Tags: Yes List Limit: 5 (for demonstration purposes only) FrontEnd Settings View user Groups: Public Users - Guests selected Admin Settings The minimum values to validate the listing setup: Data View Fields Names: id selected Data View Columns titles: id 9 Basic filters for your listing

11 Bob Janes is the author of the ChronoForms 1.3 for Joomla! site Cookbook published by Packt Publishing. He provides support on the ChronoEngine forums and works as a developer of custom applications (often using Chrono- Forms and ChronoConnectivity) for Joomla! and WordPress. Bob can be contacted at info@greyhead.net ChronoConnectivity is a Joomla! Component that works with ChronoForms to allow the easy display of lists of records from a database table. Chrono- Connectivity and ChronoForms are published by ChronoEngine.com. This help-sheet was written for ChronoConnectivity 2.0 RC3 ChronoEngine Tutorials by Bob Janes are licensed under a Creative Commons Attribution-NonCommercial-No- Derivs 3.0 Unported License Disclaimer To the best of our knowledge and belief the information in this tutorial was substantially correct at the time of writing. Neither the author, nor ChronoEngine.com shall have neither liability nor responsibility in respect of any loss or damage caused, or alleged to have been caused, directly or indirectly, by the information contained in this document. 10 Basic filters for your listing