1. Further improvements are, however, needed, especially in areas of redundancy and data security.
2. Add a to primary key every database table to uniquely identify each record.
3. If reference is made to a primary key from another table, this is termed a foreign key.
4. A compound key is a key that consists of multiple columns, because one column is not sufficiently unique.
5. A special data structure that serves the processes of accessing relationship information by storing specific values that correspond to portions of the relationship content is the concept of a database index.
6. Referential integrity is a relational database concept, which states that table relationships must always be consistent.
7. MySQL is a very powerful program in its own right. It handles a large subset of the functionality of the most expensive and powerful database packages.
8. Software programmers are well acquainted with database concepts through relational databases like Oracle, SQL SERVER and MySQL, etc.
Объяснение:
he is angry with..
they are angry with..
we are angry with..
we sit..
she sits..
you sit..
they sit..
you often help..
I often help..
she often helps..
they often help..