9 Questions
What type of join eliminates one of the duplicate columns in the result table?
Natural join
Which type of join includes all columns from each table and an instance for each row of each table?
Union join
In which type of join are rows included in the result table only if they have matching values in common columns?
Equi-join
What is the relational operation that causes two or more tables with a common domain to be combined into a single table or view?
Join
In which type of join are rows that do not have matching values in common columns included in the result table?
Outer join
What does the ON clause perform in a join?
Equality check for common columns
In a 1:M relationship, what are the common columns in joined tables usually?
Primary key of the dominant table and foreign key of the dependent table
What does a union join include from each table?
All columns
What type of join causes two or more tables with a common domain to be combined into a single table or view?
Equi-join
Study Notes
Join Types
- Natural Join: eliminates one of the duplicate columns in the result table.
Cartesian Product (Cross Join)
- includes all columns from each table and an instance for each row of each table.
Inner Join
- includes rows in the result table only if they have matching values in common columns.
Union Operation
- combines two or more tables with a common domain into a single table or view.
Outer Join (Left, Right, Full)
- includes rows that do not have matching values in common columns in the result table.
ON Clause
- specifies the condition for which rows are included in the result table.
1:M Relationship
- common columns in joined tables are usually the foreign key in the 'many' table and the primary key in the 'one' table.
Union Join
- includes all rows from both tables, with duplicate rows removed.
Test your knowledge on relational operations and joins with this quiz. Explore the concepts of join, equi-join, natural join, and outer join, and understand how they are used to combine tables in a database.
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