SQL is a critical component of many modern sites, and if you have a site with dynamic content in it, you will almost always need to store things in some sort of database. And while working with those databases, writing SQL queries and so on is a requirement of the Web developer and a typical webmaster will usually not have to touch on those points, it’s still a good idea to have at least some grasp of the language and know how a database works, so that when the time comes to get your hands dirty and there’s no one to help you, you won’t find yourself completely lost.
Sure, you can probably create new tables through the graphic interface that you’re using, but sometimes it can pay to know your way around the actual commands that are issued behind the scenes when you do that. In some cases, you will need a bit more control over the way the table is structured, and you won’t be able to get the job done with the regular interface.
This is especially true when you need to set something more specific like complex foreign keys. Plus, when you know that you’re typing the command yourself, you can easily follow it step by step instead of having to verify that everything is ticked correctly in a graphical interface.
When you need to create a backup of a table, sometimes it’s just a matter of a simple operation on the command line and you don’t need any complex procedures with the graphical interface to get the job done. It’s often as easy as creating a new table – or copying an existing one – and transferring the records. You can even set up some scripts to semi-automate the creation of new backup tables, allowing you to have a structured historical record that lets you easily compare tables and see what’s changed.
Keep in mind that this style of backing up a table is actually a bit of a workaround and may not be ideal for all cases where you need to preserve some data. In some situations, you’ll want to come up with a more comprehensive solution that covers all your bases adequately and doesn’t have the potential to miss something in the backup process. But when you just need to copy a table or move it around, you don’t need to rely on any complex solutions for that – you can just type in a couple of SQL queries to get the job done.
Pruning old records
Having trouble keeping your tables tidy? As time goes by, you might find that you’re collecting a lot of redundant information that is just piling up and taking up extra space for no reason. Even text can quickly accumulate in this manner, and it’s important to ensure that your databases are in a clean state as regularly as possible. This means occasionally pruning some old records that are no longer relevant.
How do you do that though? Obviously, you shouldn’t just go around selecting each piece of data manually and deleting them one by one. SQL gives you various tools to help you get that job done much more easily, such as filtering a table by the value of one of its columns. So, for example, if you want to get rid of data that are beyond a certain date, all it takes is one query to get the appropriate set from the table, and then you can either delete the rows directly, set them as inactive in your schema, or do something else with it that removes it from use.
Making small changes on the fly
Sometimes you don’t need to dig through countless menus just to make one small change to a table. For example, a flag on a user account, or something else that may normally take a long time to modify, can sometimes be done much more simply with the help of a few commands. Knowing your way around the current schema used by your sites can help quite a lot here too, as you’ll immediately know which tables and columns to consider in your search, and it shouldn’t take you too long to find the right field.
However, proceed with caution – there are some cases where making a small change like this can actually have a harmful effect on the site as a whole. If a field in a table is linked to other fields through another table or through some script, this can break the functionality of the whole site by just making one small change. Make sure you familiarize yourself with the way your databases are setup before attempting any such modifications to the tables. Other than that though, you should find this to be a very handy way to make small, quick changes on the fly.