1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
1
00:00:00,140 --> 00:00:03,202
Okay. So this is what I've done as you see,
2
00:00:03,202 --> 00:00:06,130
it looks a little nicer than it was before. And I didn't
3
00:00:06,130 --> 00:00:08,530
really change that much. I just made a few changes, so
4
00:00:08,530 --> 00:00:11,560
I just wanted to point them out to you, so that you
5
00:00:11,560 --> 00:00:13,690
know what they are. And the main thing, one of the
6
00:00:13,690 --> 00:00:18,210
main things I did is really to introduce these derived attributes. So
7
00:00:18,210 --> 00:00:19,860
these are attributes that are basically
8
00:00:19,860 --> 00:00:22,520
computed. Based on some other attributes.
9
00:00:22,520 --> 00:00:26,010
Okay, they don't have a value themselves, but their value is computed.
10
00:00:26,010 --> 00:00:28,900
And I used two. The first one is age. So
11
00:00:28,900 --> 00:00:31,930
basically we know the age of the patron based on
12
00:00:31,930 --> 00:00:34,920
the birthday, of the patron. So you guys, I don't
13
00:00:34,920 --> 00:00:37,150
know if you have that information currently in the system.
14
00:00:37,150 --> 00:00:38,480
>> No, we'll have to add that to the
15
00:00:38,480 --> 00:00:40,280
form patrons fill out, when they get their card.
16
00:00:40,280 --> 00:00:42,255
>> Is that, that an issue? Can you do it?
17
00:00:42,255 --> 00:00:44,130
>> No yes, we, we can easily do that.
18
00:00:44,130 --> 00:00:46,670
>> Okay, so then, perfect. So we'll do it that way. I think it's
19
00:00:46,670 --> 00:00:51,310
a, in a little cleaner. And similarly, since you told me that the fine
20
00:00:51,310 --> 00:00:54,480
was computed based on the amount of days that an
21
00:00:54,480 --> 00:00:58,310
item was late. The patron was late returning the item, then I
22
00:00:58,310 --> 00:01:02,010
also added this as a derived attribute that is computed based on
23
00:01:02,010 --> 00:01:05,140
the due date and when the item is actually returned.
24
00:01:05,140 --> 00:01:05,780
>> Makes sense.
25
00:01:05,780 --> 00:01:08,389
>> Makes sense? Okay. And the rest
26
00:01:08,389 --> 00:01:10,590
is kind of really minor things. So the, the only one I
27
00:01:10,590 --> 00:01:14,340
want to point out is I didn't, you know, discuss that with
28
00:01:14,340 --> 00:01:17,260
you before, but I added this, which is called cardinality
29
00:01:17,260 --> 00:01:20,700
for some of these relationships. And what they say is basically
30
00:01:20,700 --> 00:01:25,360
is how many elements are involved in the relationship.
31
00:01:25,360 --> 00:01:26,580
>> So, you mean the stars?
32
00:01:26,580 --> 00:01:27,960
>> Yeah, like the stars and the one...
33
00:01:27,960 --> 00:01:28,290
>> Okay.
34
00:01:28,290 --> 00:01:31,380
>> Here for example, this is telling you that for each item there
35
00:01:31,380 --> 00:01:35,490
is only one title. And that for each title, there are multiple items.
36
00:01:35,490 --> 00:01:36,490
>> So, star means many.
37
00:01:36,490 --> 00:01:37,716
>> Stars mean many, yeah.
38
00:01:37,716 --> 00:01:39,045
>> Okay, go you.
39
00:01:39,045 --> 00:01:42,321
>> Sorry that's kind of computer science lingo - we use the star
40
00:01:42,321 --> 00:01:45,500
for that kind of stuff. And, similarly, for the patron, it's
41
00:01:45,500 --> 00:01:48,510
telling me that, you know, each patron can have multiple, can
42
00:01:48,510 --> 00:01:52,550
request multiple titles, and that the same title can be requested
43
00:01:52,550 --> 00:01:55,650
by multiple patrons, which I think is the way the system works.
44
00:01:55,650 --> 00:01:59,080
>> Right. So except for these minor changes,
45
00:01:59,080 --> 00:02:01,850
we already had a pretty good model in our hands, so
46
00:02:01,850 --> 00:02:04,620
I think is a, we can finalize this and then just
47
00:02:04,620 --> 00:02:07,350
move to the low level design and then implementation, and be
48
00:02:07,350 --> 00:02:07,970
done with the system.
49
00:02:07,970 --> 00:02:08,979
>> Sounds good.
|
