1 00:00:00,000 --> 00:00:04,189 [MUSIC] 2 00:00:04,189 --> 00:00:08,708 In this modern competitive business environment, the companies that learn how 3 00:00:08,708 --> 00:00:13,740 to use the mountains of data they've captured have a competitive advantage. 4 00:00:13,740 --> 00:00:17,740 Knowledge is power and the databases are the foundation of that knowledge. 5 00:00:19,080 --> 00:00:21,400 For the purposes of our SQL courses, 6 00:00:21,400 --> 00:00:27,030 the databases that we've been using have been small, with only hundreds of rows. 7 00:00:27,030 --> 00:00:30,115 In the real world, databases are very large, 8 00:00:30,115 --> 00:00:32,565 having millions of rows in a single table. 9 00:00:33,875 --> 00:00:38,125 These commonly used databases are called relational databases. 10 00:00:38,125 --> 00:00:41,175 This term came about from structuring databases 11 00:00:41,175 --> 00:00:46,295 in a way that tables are linked to each other by shared attributes. 12 00:00:46,295 --> 00:00:49,633 These links are the relationships between tables. 13 00:00:49,633 --> 00:00:54,080 As an organization's data needs grow, 14 00:00:54,080 --> 00:00:58,240 they need a database that can grow and scale with them. 15 00:00:58,240 --> 00:01:03,160 How a database schema is designed has a tremendous impact on the types of 16 00:01:03,160 --> 00:01:08,150 reports that they can generate and the performance of that database. 17 00:01:08,150 --> 00:01:12,330 There are many reasons why relational databases became the standard for 18 00:01:12,330 --> 00:01:14,600 application data storage. 19 00:01:14,600 --> 00:01:20,830 A few of which are eliminating redundant data reduces storage requirements on disk. 20 00:01:20,830 --> 00:01:26,140 Well structured and properly segmented data can be accessed and modified quickly. 21 00:01:26,140 --> 00:01:29,350 Bad data leads to bad reports. 22 00:01:29,350 --> 00:01:32,644 Relational databases allow schema designers to enforce 23 00:01:32,644 --> 00:01:37,043 good data principles which lead to better data quality and better reports. 24 00:01:37,043 --> 00:01:41,831 If you imagine unstructured data in a poorly designed database schema, 25 00:01:41,831 --> 00:01:43,486 it might look like this. 26 00:01:43,486 --> 00:01:48,450 But if you picture organizing your data with a more thoughtful approach, 27 00:01:48,450 --> 00:01:51,530 it might start to look like this. 28 00:01:51,530 --> 00:01:57,080 This is what relational databases do, they organize data into related tables 29 00:01:57,080 --> 00:02:01,544 that give context and meaning to the words and numbers contained within. 30 00:02:02,845 --> 00:02:03,895 Hi, I'm Andrew, 31 00:02:03,895 --> 00:02:08,065 a database user, a lifelong learner and teacher here at Treehouse. 32 00:02:08,065 --> 00:02:12,635 In this course, we're going to be learning a lot about relational databases and 33 00:02:12,635 --> 00:02:17,085 writing complex SQL queries and joining relational data together. 34 00:02:18,205 --> 00:02:19,635 In the upcoming videos, 35 00:02:19,635 --> 00:02:24,570 we'll be taking a look at the concepts that make relational databases work. 36 00:02:24,570 --> 00:02:28,000 And start thinking about data in terms of sets 37 00:02:28,000 --> 00:02:30,860 as opposed to individual values or rows.