C100DBA CRUD Operations Practice Question
Which THREE of the following are valid MongoDB CRUD query operators?
⚠ Common exam trap
Candidates frequently include non-existent or update-only operators like $set or $update in the list of valid query operators, failing to distinguish between filtering and modification syntax.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
$gt
MongoDB provides a rich set of query operators for filtering and modifying data. Operators like $gt, $ne, and $exists are staples of the query language. Mastering these allows developers to construct complex, powerful queries to extract specific data subsets. Understanding the syntax and behavior of these operators is a key requirement for the C100DBA certification and effective day-to-day database administration work.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
$gt
Why this is correct
$gt is a comparison operator that selects documents where the value of a field is greater than a specified value. It is essential for range queries, such as finding products with prices above a certain threshold or retrieving records created after a specific timestamp.
- ✓
$ne
Why this is correct
$ne is a comparison operator that selects documents where the value of a field is not equal to a specified value. It is frequently used for filtering out specific status codes or values from a result set, providing a negative condition for document selection.
- ✗
$and_not
Why it's wrong here
$and_not is not a valid MongoDB query operator. MongoDB uses $not as a logical negation operator, or simply uses $ne for inequality. The existence of non-existent operators like $and_not is a common distractor to test the candidate's actual familiarity with the official MongoDB operator list.
- ✓
$exists
Why this is correct
$exists is a query operator used to check whether a specified field exists in a document. This is useful for finding documents that have missing data or for verifying that a new schema property has been populated across the collection, which is vital for database maintenance.
- ✗
$is_null
Why it's wrong here
$is_null does not exist in MongoDB. To query for null values, you match against the null value directly (e.g., {field: null}). This will return documents where the field is null or where the field does not exist at all. This is a common point of confusion for new developers.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official MongoDB exam blueprint
This C100DBA practice question is part of Courseiva's free MongoDB certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the C100DBA exam.