![]() ![]() It's also a handy tool for web developers to test new CSS on a site without taking it live or pushing it to a server. Not only that, but you can customize any site pretty much any way you want, not just Dark Mode it - insert your own background images, make accent colors whatever you want, just about anything you can imagine with CSS. The great thing about an extension like this is that you can install or create custom styles specifically designed for certain sites. There are some extensions on the Mac App Store to apply a sort of global dark theme, but because these extensions usually apply one general look to tons of websites, they sometimes break sites or just look ugly. If you love Mojave's Dark Mode like I do, you probably hate seeing websites with bright white themes. This meant that Safari was soon to be left without a way to install custom styles for sites, which I use all the time! So I made Cascadea, which is a new Mac app and matching App Extension for Safari supporting both macOS High Sierra and macOS Mojave. Marks of the student (int) is a regular column.I know there's been a lot of talk on this sub recently about Apple's new policies on Safari extensions - existing extensions are going away, and Safari App Extensions are the way of the future. ![]() Primary key: Enrollment number (int), name (varchar(20)) ![]() Name (varchar(20)), email-id (varchar(20)), and State of the student (varchar(20)) are regular columns. Setting up DatabaseĪs we have three tables, T1, T2, and T3, each table should be in the following format. To do so, we will define our database more efficiently. Using a similar example, we will learn how to use CASCADE in SQL while deleting/updating an entry in the parent and child table. With a single command, we can change all three tables simultaneously. We use the keyword CASCADE to overcome this problem in SQL queries. If we try to perform the scenarios provided in the above cases in a traditional fashion, the changes would need to be done manually in all three tables. As the student will be shifted to another class, so his information needs to be deleted.Ĭase 2: If a student wants to change his name/enrollment number, he has to update all three tables, i.e., T1, T2, and T3. Now, if there is a case where a student wants to change a class or change his name/enrollment number, we need to make certain changes in the database.įollowing is the design of our MySQL database (arrangement of tables).Ĭase 1: If a student wants to change his class, he must delete his name from all the tables, i.e., T1, T2, and T3. Both tables, T2 and T3, have three columns, i.e., enrollment number, name of the students, and marks of the student. Table T3 contains the marks of all the students in the Science subject. Table T2 contains the marks of all the students in the Mathematics subject. Let us now consider two more tables, i.e., T2 and T3. Table T1 has four columns, i.e., Enrollment number, name, email, and state of the student. Let us take an example in layman's terms to understand the usage of cascade keyword in SQL.Ĭonsider a table named T1 which contains the data of all the students in a class.
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