1 00:00:00,000 --> 00:00:03,775 Hello and welcome to SQL for data science. 2 00:00:03,775 --> 00:00:07,310 First, we will talk a little bit about what you'll learn in this course. 3 00:00:07,310 --> 00:00:12,410 This course teaches you the basics of the SQL language and the relational database model. 4 00:00:12,410 --> 00:00:14,685 There will be some lab exercises, 5 00:00:14,685 --> 00:00:16,225 and at the end of each section 6 00:00:16,225 --> 00:00:17,990 there are a few review questions. 7 00:00:17,990 --> 00:00:20,585 And at the end, there is a final exam. 8 00:00:20,585 --> 00:00:22,310 By the end of this course, 9 00:00:22,310 --> 00:00:25,210 you will be able to discuss SQL basics and 10 00:00:25,210 --> 00:00:28,730 explain various aspects of the relational database model. 11 00:00:28,730 --> 00:00:33,360 In this video, we will learn about SQL and relational databases. 12 00:00:33,360 --> 00:00:35,105 By the end of this video, 13 00:00:35,105 --> 00:00:38,190 you will be able to describe SQL, data, 14 00:00:38,190 --> 00:00:44,305 database, a relational database, and list five basic SQL commands. 15 00:00:44,305 --> 00:00:50,510 But wait, what is SQL and what is a relational database? What is SQL? 16 00:00:50,510 --> 00:00:56,555 SQL is a language used for relational databases to query or get data out of a database. 17 00:00:56,555 --> 00:01:00,680 SQL is also referred to as SQL 18 00:01:00,680 --> 00:01:05,405 and is short for its original name Structured English Query Language. 19 00:01:05,405 --> 00:01:09,290 So SQL is a language used for a database to query data. 20 00:01:09,290 --> 00:01:12,945 But what is data and what is a database? 21 00:01:12,945 --> 00:01:16,115 Data is a collection of facts in the form of words, 22 00:01:16,115 --> 00:01:18,290 numbers, or even pictures. 23 00:01:18,290 --> 00:01:21,715 Data is one of the most critical assets of any business. 24 00:01:21,715 --> 00:01:24,490 It is used and collected practically everywhere. 25 00:01:24,490 --> 00:01:26,965 Your bank stores data about you, your name, 26 00:01:26,965 --> 00:01:29,900 address, phone number, account number et cetera. 27 00:01:29,900 --> 00:01:34,075 Your credit card company and your paypal accounts also store data about you. 28 00:01:34,075 --> 00:01:36,640 Data is important; so, it needs to be 29 00:01:36,640 --> 00:01:39,910 secure, and it needs to be stored and accessed quickly. 30 00:01:39,910 --> 00:01:41,560 The answer is a database. 31 00:01:41,560 --> 00:01:44,240 So, what is a database? 32 00:01:44,240 --> 00:01:50,030 Databases are everywhere and used every day, but they are largely taken for granted. 33 00:01:50,030 --> 00:01:52,205 A database is a repository of data. 34 00:01:52,205 --> 00:01:54,830 It is a program that stores data. 35 00:01:54,830 --> 00:01:58,625 A database also provides the functionality for adding, 36 00:01:58,625 --> 00:02:00,965 modifying, and querying that data. 37 00:02:00,965 --> 00:02:04,590 There are different kinds of databases of different requirements. 38 00:02:04,590 --> 00:02:07,395 The data can be stored in various forms. 39 00:02:07,395 --> 00:02:09,885 When data is stored in tabular form, 40 00:02:09,885 --> 00:02:13,310 the data is organized in tables like in a spreadsheet, 41 00:02:13,310 --> 00:02:15,135 which is columns and rows. 42 00:02:15,135 --> 00:02:17,160 That's a relational database. 43 00:02:17,160 --> 00:02:21,175 The columns contain properties about the item such as last name, 44 00:02:21,175 --> 00:02:24,255 first name, email address, city. 45 00:02:24,255 --> 00:02:27,380 A table is a collection of related things like 46 00:02:27,380 --> 00:02:30,365 a list of employees or a list of book authors. 47 00:02:30,365 --> 00:02:32,125 In a relational database, 48 00:02:32,125 --> 00:02:35,190 you can form relationships between tables. 49 00:02:35,190 --> 00:02:38,370 So a database is a repository of data. 50 00:02:38,370 --> 00:02:42,160 A set of software tools for the data in the database is called 51 00:02:42,160 --> 00:02:46,615 a database management system or DBMS for short. 52 00:02:46,615 --> 00:02:50,965 The terms database, database server, database system, 53 00:02:50,965 --> 00:02:56,270 data server, and database management systems are often used interchangeably. 54 00:02:56,270 --> 00:03:04,335 For relational databases, it's called a relational database management system or RDBMS. 55 00:03:04,335 --> 00:03:08,510 RDBMS is a set of software tools that controls 56 00:03:08,510 --> 00:03:12,985 the data such as access, organization, and storage. 57 00:03:12,985 --> 00:03:18,785 And RDBMS serves as the backbone of applications in many industries including banking, 58 00:03:18,785 --> 00:03:21,585 transportation, health, and so on. 59 00:03:21,585 --> 00:03:25,570 Examples of relational database management systems are 60 00:03:25,570 --> 00:03:28,280 my SQL, Oracle Database, 61 00:03:28,280 --> 00:03:36,120 DB2 Warehouse, and DB2 on Cloud. For the majority of people using a database, 62 00:03:36,120 --> 00:03:39,255 there are five simple commands to create a table, 63 00:03:39,255 --> 00:03:41,690 insert data to populate the table, 64 00:03:41,690 --> 00:03:43,835 select data from the table, 65 00:03:43,835 --> 00:03:46,205 update data in the table, 66 00:03:46,205 --> 00:03:48,730 delete data from the table. 67 00:03:48,730 --> 00:03:53,195 So those are the building blocks for SQL for data science. 68 00:03:53,195 --> 00:03:56,920 You can now describe what is SQL, what is data, 69 00:03:56,920 --> 00:04:01,404 what is a database, and what is a relational database. 70 00:04:01,404 --> 00:04:06,485 You know that RDBMS stands for Relational Database Management System, 71 00:04:06,485 --> 00:04:11,135 and you can list five basic SQL commands to create a table, 72 00:04:11,135 --> 00:04:13,535 insert data to populate the table, 73 00:04:13,535 --> 00:04:15,665 select data from the table, 74 00:04:15,665 --> 00:04:17,610 update data in the table, 75 00:04:17,610 --> 00:04:20,285 and delete data from the table. 76 00:04:20,285 --> 00:04:23,200 Thanks for watching this video. 77 00:04:23,200 --> 00:04:28,000 (Music)