Custom query methods by naming convention in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a custom query method by naming convention in Spring Boot?

It is a method in a Spring Data repository interface whose name follows a pattern that Spring Data understands to create a database query automatically without writing SQL.

intermediate

How does Spring Boot know what query to run from a method name?

Spring Data parses the method name to identify keywords like findBy, countBy, and conditions like And, Or, GreaterThan, then builds the query based on the entity's fields.

beginner

Example: What does the method name findByLastNameAndAgeGreaterThan mean?

It means find all records where the lastName field matches the given value AND the age field is greater than the given number.

intermediate

Can you use custom query methods for sorting and limiting results?

Yes, by adding keywords like OrderBy and using Pageable parameters, you can sort and limit results using naming conventions.

beginner

What happens if a method name does not follow Spring Boot's naming conventions?

Spring Data will throw an error or fail to create the query because it cannot understand how to translate the method name into a database query.

Which prefix is used to create a method that returns a list of entities matching a condition?

A updateBy

B deleteBy

C insertBy

D findBy

The prefix 'findBy' tells Spring Data to find and return entities matching the condition.

What does the method name countByStatus do?

A Deletes entities with a given status

B Counts entities with a given status

C Finds entities with a given status

D Updates entities with a given status

'countBy' counts how many entities match the condition.

Which keyword would you use to combine two conditions in a method name?

A And

B Or

C Not

D Between

'And' combines two conditions that both must be true.

How do you specify sorting in a custom query method name?

A Add 'GroupBy' followed by the field name

B Add 'SortBy' followed by the field name

C Add 'OrderBy' followed by the field name

D Add 'FilterBy' followed by the field name

'OrderBy' is used to specify sorting in the method name.

What will happen if you name a method findAllUsers in a Spring Data repository?

A Spring Data will not recognize it as a query method

B It will find all users

C It will delete all users

D It will update all users

The method name does not follow the naming convention for queries, so Spring Data cannot create a query.

Explain how Spring Boot creates database queries from custom method names in repositories.

Think about how the method name tells Spring Boot what to look for in the database.

Describe how you would write a method name to find all records where age is greater than 30 and status is 'active'.

Combine conditions with 'And' and use comparison keywords.