Table models

Содержание и основные понятия

Back to the table of contents
Alterna · Chapter 23 · page 23.2
Table models
When an object is described in rows and columns: types of tables, formulas, calculation by matrix.
Table Information Model
It's a way of describing an object as a table. The lines and columns are objects or properties, and in cells are values. For GEF/OPF, it's the main way to systematize the same type of data.
GEF
PIF
OGE No. 14
EEG No. 1.9
01
Three main types of tables
Object of property, object of object, binary matrix
GEF
(1) "Intrusion — Property"
One line is one object. One column is one property. In a cell, the value of this characteristic is that of this object.
Student
Height, cm
Weight, kg
Grade
Anya.
165
52
9A
Bore
172
63
9B
Vica
160
48
9A
(2) Subject - Object
The lines are objects of the same type, columns are those of the other type, and in the cell is the connection between them (distance, time, availability).
City
Moscow
Tula
Kaluga
Moscow
—
180
190
Tula
180
—
110
Kaluga
190
110
—
Kilometers between cities, the main diagonal is empty.
3) Bibliographic matrix (matrix of relationships)
Same type of object, but only in the cell.
0
or
1
It's used for graphs, related relationships, relationships.
A
B
B
G
A
0
1
1
0
B
1
0
0
1
B
1
0
0
1
G
0
1
1
0
"1" means the rib between the vertices. Symmetrical to the main diagonal (A-B = B-A).
02
Calculation formulas
How many lines, columns, cells
If in the table
M
Line and
N
Columns:
Всего клеток
= M · N
Информационный объём
= M · N · i бит (i — сколько бит на одно значение)
Example: Table of achievement for 30 students in 12 subjects, estimates from 2 to 5 (N=4, i=2 bits):
Клеток: 30 · 12 = 360
Объём: 360 · 2 = 720 бит =
90 байт
03
Table calculator
Determine the size of the table and how much memory it takes
Knowing
M
Line
N
columns and the number of possible values, can be calculated:
Total cells
= M × N
Beats one cage.
= .log2(s)
Grouping tables in bits
= M × N × bit
For example, a magazine of 30 pupils x 12 subjects, estimates of 2 - 5 (4 values = 2 bits): 30 x 12 x 2 = 720 bits = 90 bytes.
📊
Table Options
Line M
Columns N
Possible values
Введи параметры и нажми «Рассчитать».
04
SQL Symulator
Make a request for the table and get the result, as in the real database.
GEF
EEG No. 13
🗄️
Interactive SQL trainer
Table
Students
- Class database:
ID
First name
Age
Grade
Ball
1
Alice.
15
9A
85
2
Boris.
16
9B
92
3
Vica
15
9A
78
4
Gleb
16
10A
88
5
Dasha
15
9B
95
6
Egor
16
10A
72
7
Jeanne.
15
9A
90
8
Zahar
16
10B
81
Job 1 / 8
+50 XP
Columns
Field
Condition
Meaning
Sorting
SELECT * FROM Students
05
Logical tasks with tables
Dwin matrices to solve puzzles - bet 1 or 0
GEF
EGE No. 1
🧩
4 Tasks: Binary matrix
06
Mini-test: 5 questions
XP: 0