How do you implement one-to-one, one-to-many and many-to-
many relationships while designing tables?
Answers were Sorted based on User's Feedback
Answer / swapna
One-to-One relationship can be implemented as a single
table and rarely as two tables with primary and foreign key
relationships.
One-to-Many relationships are implemented by splitting the
data into two tables with primary key and foreign key
relationships.
Many-to-Many relationships are implemented using a junction
table with the keys from both the tables forming the
composite primary key of the junction table.
It will be a good idea to read up a database designing
fundamentals text book.
Is This Answer Correct ? | 48 Yes | 2 No |
Answer / harish sharma
All relationships are implemented by primary key and
foreign keys.
One-to-one
When we use two tables to relate by one primary key in one
table and one foreign key in secound table.
for example Employee table and salary table.
One-to-many
When we use many table but primary key is only in one table
and in other tables we use foreign key to inter-relate
tables.
For example Emp_id(primary key) in Employee table is
assosiated with salary_emp_id (foreign key) in Salary table
and associated with tax_emp_id (foreign key) in
tax_collecation table and associated with pf_emp_id
(foreign key) in provident_fund table.
Many-to-many
When we use primary keys of two or more tables in a
saperate table and in this table we relate these with other
tables by foreign key and primary key
Is This Answer Correct ? | 18 Yes | 9 No |
Answer / sundar
One-to-One relationship can be implemented as a single
table and rarely as two tables with primary and foreign key
relationships.
One-to-Many relationships are implemented by splitting the
data into two tables with primary key and foreign key
relationships.
Many-to-Many relationships are implemented using a junction
table with the keys from both the tables forming the
composite primary key of the junction table.
Is This Answer Correct ? | 7 Yes | 2 No |
How to get a list of columns in a view using the "sp_help" stored procedure?
Can a table be created inside a trigger?
Do you think BCNF is better than 2NF & 3NF? Why?
What is user-defined scalar function?
What is normalization?
What are triggers in ms sql server?
What is serializable?
What is co-related sub query?
What is self contained scalar sub query?
Explain indexed views?
Can sql server be linked with other servers like oracle?
Every night you run a full backup after every 3 three hours you make a differential backup every hour you make an incremental backup in a worst-case scenario, how much work you can lose?