Author: Tom (Page 371 of 427)

A WordPress Database Index Reference

October 29, 2012 / Tom / 0 Comments

When it comes to building web applications, all of the major components can be reduced to the following pieces:

Frontend
Middleware
Database

Yes, there are a lot of moving pieces in each of these layers, and there are even layers within layers, but this is generally the architecture that you’re going to find 99% of the time.

And WordPress is no different.

One of the most important aspects of working with web applications that’s often over looked by both beginner and advanced developers alike is the significance of indexes on the underlying database (and I’m certainly not exempt from this).

For any middleware that provides an API for retrieving data from the database, the API is translating the server-side code into database queries. Assuming that the database schema is properly organized, and assuming that you’re leveraging the API properly, you should see very little performance issues.

But if you treat the database as a black box and rely solely on the API, you could be inadvertently affecting the performance of your theme, plugin, or application by constructing poor queries.

I typically keep a short reference of the WordPress Database Index and thought I’d share it here just as much for myself as for you guys.

Using WP_User_Query To Retrieve Users Across Multiple Roles

October 26, 2012 / Tom / 0 Comments

I’ve covered WP_User_Query in a previous post. In short, WP_User_Query is the preferred method for retrieving user information from the database when working with custom queries.

One of the shortcomings of this API method is that it doesn’t allow you to query across multiple roles. So, for example, if you want to retrieve users that meet a certain criteria but may span across multiple roles – say editors and administrators – the API doesn’t support it.

That said, there is a simple strategy that can be used with WP_User_Query to retrieve users across multiple roles.

Properly Calculating Page Offset in Custom WordPress Queries

October 25, 2012 / Tom / 0 Comments

Whenever it comes to writing custom queries in WordPress, pagination always seems to give developers problems (myself included!).

I think this can be chalked up to the next / previous pagination links (so does next mean older, or newer?), paginating single posts as well as archive posts, and then occasionally having to write custom queries that include pagination.

One of the areas that I see most confusing – again for myself as well – is properly calculating page offsets especially when working with the WP_Query offset parameter.

The thing is, I think it can be much more simplified (or, perhaps, demystified?) when visualizing the data that you’re working with, and knowing how to use some of the existing API links.

So here’s what you need to know in order to get pagination working when working with the WP_Query offset, page, and number parameters.

A Presentation on The WordPress Settings API

October 24, 2012 / Tom / 0 Comments

In the past, I’ve written extensively about the WordPress Settings API, how to introduce unit testing into projects using the WordPress Settings API, as well as my thoughts on frameworks in contrast to the Settings API.

Clearly, I’m an advocate for using this particular part of the API.

How To Setup Custom Queries For WP_Query Pagination

October 23, 2012 / Tom / 0 Comments

One of the nicest things about using WP_Query is that it allows you to completely customize the data that you’re bringing back to the front end.

For those of you who are completely unfamiliar with this API, it’s a powerful class that allows you to custom tailor a query against the WordPress database for retrieving information about posts, pages, custom post types, and so on.

If you’re using one of the more common features of WordPress, such as those mentioned above, then it’s relatively easy to get started; however, if you’re doing more complicated work, such as including multiple custom queries in a single view, then there are some challenges that you may discover.

Personally, I’ve been working on a project where I have two custom queries running in a template and I needed to paginate the results. The problem is that using the usual functions for doing this, that is:

Were not working as expected.

Ultimately, it required me passing a little bit more information to the query’s arguments array and to the pagination link functions. Here’s how you can setup WP_Query Pagination to work properly in custom queries.