Database systems

Question 1

Path from modeling to creation of a database

Answer 1

1 ) Identify entities

2) Define relationships
3) Determine PK
4) Conversion into physical data model
5) Determine consistency conditions
6) Formulate transactions

Question 2

Consistency conditions

Answer 2

All ID attributes are truly unique
Format and value range compliance
Preservation of referential integrity

Question 3

Text types in SQL

Answer 3

CHAR(n) - character strings with always exactly n characters
VARCHAR(n) - character strings with limited characters
TEXT - very long character string, allowed size limited big DBMS

Question 4

Number types in SQL

Answer 4

DECIMAL- specifies the exact number of decimal places required
INT- integers (heel getal)
REAL- floating point number

Question 5

Other data type

Answer 5

VARBINARY(n) - binary types with variable length, but not more than n characters
BOOLEAN - boolean values