Table of Contents
- 1 Why would we want to split data into separate tables?
- 2 Why do you think organizing data into tables and relationships is a good way to design a database How do related tables improve the accuracy of data in a database?
- 3 What is the benefit of having the dataset split into several tables?
- 4 Why is it better to have well organized data in tables you create?
- 5 Which of the following is used to represent the relationships between two relations tables )?
- 6 Can a table be created without primary key?
Why would we want to split data into separate tables?
But, tables are often not designed to be readable to humans– they’re designed to be the easiest to maintain and least prone to bugs. In many cases, it may be best to split information into multiple related tables, so that there is less redundant data and fewer places to update.
A good database design is, therefore, one that:
- Divides your information into subject-based tables to reduce redundant data.
- Provides Access with the information it requires to join the information in the tables together as needed.
- Helps support and ensure the accuracy and integrity of your information.
Which key is required to create a relationship between two or more tables?
A foreign key helps to define the relationship among tables . This unique key communicates one or more interrelationships in a relational database between two or more tables.
Do foreign keys need to be in both tables?
Since the purpose of the foreign key is to identify a particular row of referenced table, it is generally required that the foreign key is equal to the candidate key in some row of the primary table, or else have no value (the NULL value.). This rule is called a referential integrity constraint between the two tables.
What is the benefit of having the dataset split into several tables?
This reduces storage space and improves performance. It also can allow more flexibility- for example if a table of people had their address stored in a separate table, people could then have an unlimited number of addresses- something that could not be accomplished if one tried to store the addresses in the same table.
Why is it better to have well organized data in tables you create?
A table helps you recognize the relationships among data and evaluate the data more effectively. Once your data is organized into a table, it is easier to evaluate and to determine if a chart or a graph would be helpful. Also, a table makes it easier to put data into a chart or a graph.
What is the purpose of creating relationship in DBMS?
A relationship, in the context of databases, is a situation that exists between two relational database tables when one table has a foreign key that references the primary key of the other table. Relationships allow relational databases to split and store data in different tables, while linking disparate data items.
Which field is always on the one side of a one-to-many relationship between two tables?
In a one-to-many relationship between two tables, the foreign key field is the field in the “many” table that links the table to the primary key field in the “one” table.
Which of the following is used to represent the relationships between two relations tables )?
Foreign key is used to represent the relationship between two tables.
Can a table be created without primary key?
Every table can have (but does not have to have) a primary key. The column or columns defined as the primary key ensure uniqueness in the table; no two rows can have the same key. The primary key of one table may also help to identify records in other tables, and be part of the second table’s primary key.