Database Design 9 - More Database Terms — Transcript

Full transcript

1. 0:00hey everyone welcome back this video
2. 0:02will be just some more vocabulary uh
3. 0:04hopefully it's not 12 minutes long like
4. 0:06the last one but we'll do our best all
5. 0:09right so these ones are there's not as
6. 0:11many we brok it up into two categories
7. 0:13this one first one is SQL so first we
8. 0:16learned
9. 0:16about uh SQL which obviously is program
10. 0:20language used to uh it's by the way I
11. 0:23never even mentioned this I'm horrible
12. 0:24structured query language is what SQL
13. 0:26means what that's what it stands for
14. 0:29it's used to to uh connect to your
15. 0:32database I sorry I just got distracted I
16. 0:35was waving this paper and like my lens
17. 0:37is like flashing for some
18. 0:41reason anyways
19. 0:43uh the next part was data definition
20. 0:46language which is used to define it's
21. 0:49part of SQL so SQL has data definition
22. 0:52language and
23. 0:54DML uh data manipulation language ddl is
24. 0:57used to define the structure of our
25. 1:00database data manipulation language is
26. 1:03used to insert values in our database as
27. 1:07well as uh update them delete values and
28. 1:12search values and so forth the other
29. 1:15thing was I never really mention this
30. 1:17but I do want to mention it here
31. 1:19SQL
32. 1:21keywords so anytime we have the word
33. 1:24keywords in a programming language it's
34. 1:26talking about something that is reserved
35. 1:28that you're not supposed to to use for
36. 1:30your userdefined data so for
37. 1:34example select an
38. 1:37SQL this is a word that your database is
39. 1:41going to
40. 1:42recognize as okay we want you to do
41. 1:45something we want you to select data
42. 1:47it's a keyword because it's already
43. 1:49defined so I wouldn't I don't want to
44. 1:51name my tables or my columns any
45. 1:55keywords cuz it can cause errors or
46. 1:58confusion or just mix things complicated
47. 2:01uh I always put SQL keywords in capital
48. 2:05letters all right so that's pretty much
49. 2:07all for the
50. 2:09SQL uh here's my
51. 2:14Eraser
52. 2:16America and every other
53. 2:24country all
54. 2:26right presentation so the very first
55. 2:29thing is we have the front end of an
56. 2:34application so the front end is what the
57. 2:37user sees uh the back end is what's
58. 2:41going on behind the
59. 2:44scene when we have a website we don't
60. 2:47just have what the website looks like we
61. 2:49have code that gives us that look when
62. 2:53we put in data to forms we have
63. 2:56languages that communicate with
64. 2:58databases to
65. 3:00create a easy to follow non-confusing
66. 3:03front end but the back end is
67. 3:06complicated as
68. 3:08heck so that's the difference between
69. 3:10front end and back end front end is what
70. 3:12the any user at a particular time will
71. 3:14see the back end is what's going on
72. 3:17behind the scenes so often when we're
73. 3:19working with databases we will program a
74. 3:22front end because we don't want everyone
75. 3:24accessing our server it's insecure and
76. 3:29it's just not a good idea so we often
77. 3:31create a front-end application to access
78. 3:34our database most commonly a website
79. 3:38although there's other forms but
80. 3:40whatever so if here is our database
81. 3:43rather than people signing into the
82. 3:45server and using SQL code to get
83. 3:48information we often program front ends
84. 3:52for people to access this data in a
85. 3:56different way so each one of these front
86. 3:59ends would be like a website page for
87. 4:01example so here would be a registration
88. 4:04page here would be your users page here
89. 4:06would be uh your profile uh your
90. 4:08homepage here would be if you like you
91. 4:11can even have different tier systems so
92. 4:13this could be a page where the website
93. 4:17administrator can add or delete users
94. 4:20they have that extra privilege this is
95. 4:22also the view system which we will talk
96. 4:24about in a second well the front
97. 4:27end doesn't allow us to directly type in
98. 4:29our own SQL it only allows us to use
99. 4:33what the the front end gives us which is
100. 4:36then communicated to the database so
101. 4:39that's what a front end end is the back
102. 4:41end would be the server side code used
103. 4:44to communicate with the database so when
104. 4:47we when we're talking about clients and
105. 4:49servers we have those two terms we have
106. 4:52client and then we have
107. 4:54server so very first thing is
108. 4:58client client
109. 5:00is uh think of it if we have this wall
110. 5:02here over here we have a
111. 5:07computer and then over here we have a
112. 5:13database this is the client
113. 5:17side because we're accessing the
114. 5:21database over here is the server
115. 5:28side
116. 5:32so CL uh client side and then server
117. 5:34side I don't really have room to write
118. 5:35that but the server serves instances of
119. 5:40this database to the client where they
120. 5:42can access the data in some way depends
121. 5:45on how we the the Privileges we give
122. 5:48them so um when we talking
123. 5:52about different privileges for different
124. 5:55people we use what's known as a view so
125. 5:57first let me finish this client side and
126. 6:00server
127. 6:02side and we communicate from the client
128. 6:05side to the server side by a
129. 6:09server
130. 6:11side scripting or
131. 6:15programming
132. 6:18language oh that's
133. 6:21huge now my hands tired we can give
134. 6:24custom views so a view is just taking
135. 6:28the data from the database and
136. 6:30illustrating it in a different way than
137. 6:32how it's actually stored for example a
138. 6:35user on a website can visit let's say
139. 6:38we're on like a social network and I
140. 6:40visit my friend's
141. 6:42page it'll tell me their their name
142. 6:45possibly their username if that's what
143. 6:46they use their date of registration uh
144. 6:49their phone number if that's public for
145. 6:51example anything like that their
146. 6:53relationship status although information
147. 6:56that is private may only be accessed
148. 6:59ible to the user who owns it for example
149. 7:03their password or their email or uh
150. 7:06their friends list that might be a
151. 7:10different view depending on what page
152. 7:13you are on what page you are on and the
153. 7:16user that you are so I may be able to
154. 7:18access my own password and email but
155. 7:21that might be private to other people
156. 7:23that's the
157. 7:25view um views often use join
158. 7:29which basically connect data from
159. 7:31multiple tables to create a new table if
160. 7:34we have two tables
161. 7:37here users table comments
162. 7:46table can you see that can you see it
163. 7:49you better be able to see it well a
164. 7:51comment is always given by a user and we
165. 7:55connect it using the
166. 7:57ID it's called a foreign key
167. 8:00connection well this ID let's say it's
168. 8:03the ID of 25 right well instead of
169. 8:07having okay this comment was by the
170. 8:09person with the name uh with the user
171. 8:11with the user ID of 25 we wanted to say
172. 8:15Caleb Curry so we have a join taking the
173. 8:20name from the user table and apply and
174. 8:24connecting it with the comment of the
175. 8:26comments table to get this new t uh
176. 8:29generated table this is just a view it's
177. 8:33not actually stored in the database like
178. 8:35this we're just creating a new
179. 8:37illustration of how the data really is
180. 8:39stored and then we can have the name of
181. 8:41the person followed by the comment or
182. 8:45comments of that
183. 8:46person you may be asking why don't you
184. 8:49just use the name as a reference well
185. 8:52that's because many multiple people can
186. 8:54have the same name for example so we
187. 8:56always need something that's unique for
188. 8:58this Con connection whether if you don't
189. 9:01want to use an ID you could use
190. 9:02something like a natural key uh username
191. 9:06for example but I often use IDs and
192. 9:08we'll be talking about that more in
193. 9:10upcoming videos so yeah that is all of
194. 9:13the vocabulary that we have gone over so
195. 9:16far pretty much uh if you have any
196. 9:19questions about any of those just leave
197. 9:20a comment I recommend that you write all
198. 9:22those down I should have told you that
199. 9:24at the beginning but anyways I recommend
200. 9:26you write those down as well as the
201. 9:27definitions study those learn them and
202. 9:30especially study from the previous video
203. 9:32study all the different terms that mean
204. 9:35the same thing because um after a while
205. 9:39you get kind of used to those terms but
206. 9:43if you're just learning and you don't
207. 9:45know that these are talking about the
208. 9:48same things well then you can get
209. 9:49confused very easily so I recommend you
210. 9:52study all right a row is also called a
211. 9:54tupple and is also called a whatever
212. 9:56blah blah blah BL blah that will help
213. 9:58you that way when I say whatever word it
214. 10:01is you know what I'm talking about and
215. 10:03you don't have to like check your charts
216. 10:05or whatever or go watch other videos so
217. 10:09that's something I definitely recommend
218. 10:10that you memorize uh as well for the SQL
219. 10:13stuff it's not as important like the DML
220. 10:16ddl but I do recommend that you memorize
221. 10:20all of these terms as well so thank you
222. 10:21for watching if you enjoyed that please
223. 10:23be sure to click subscribe and I will
224. 10:25see you guys in the next video where we
225. 10:27are starting something new new so yeah
226. 10:30I'm excited hopefully you are too
227. 10:33bye peace yeah yeah yeah wow