{"id":23296,"date":"2026-09-28T04:49:26","date_gmt":"2026-09-28T04:49:26","guid":{"rendered":"https:\/\/www.examlabs.com\/certification\/?p=23296"},"modified":"2026-09-28T04:49:26","modified_gmt":"2026-09-28T04:49:26","slug":"mongodb-c100dba-practice-test-questions-and-exam-dumps-part9-q161-180","status":"publish","type":"post","link":"https:\/\/www.examlabs.com\/certification\/mongodb-c100dba-practice-test-questions-and-exam-dumps-part9-q161-180\/","title":{"rendered":"MongoDB C100DBA Practice Test Questions and Exam Dumps Part9 Q161-180"},"content":{"rendered":"

View Full <\/b>MongoDB C100DBA Exam Dumps<\/b><\/a> and Practice Test Dumps<\/b><\/h2>\n

 <\/p>\n

Question 161<\/b><\/h3>\n

Which MongoDB operator tests whether a field value is greater than a specified value?<\/b><\/p>\n

    \n
  1. $above<\/span><\/li>\n
  2. $greater<\/span><\/li>\n
  3. $gtValue<\/span><\/li>\n
  4. $gt<\/span><\/li>\n<\/ol>\n

    Correct Answer: 4<\/b><\/p>\n

    Explanation:<\/b><\/p>\n

    The $gt comparison operator matches documents where a specified field contains a value greater than the supplied comparison value. It is commonly used for numeric, date, and other comparable data types. For example, administrators can use $gt to locate records created after a particular threshold or products whose price exceeds a defined amount. Query performance depends on data distribution and available indexes. DBAs should verify the field type and comparison semantics when using range predicates. Explain plans can help determine whether an appropriate index is being used efficiently for frequently executed $gt queries.<\/span><\/p>\n

    Question 162<\/b><\/h3>\n

    Which MongoDB operator matches values less than or equal to a specified threshold?<\/b><\/p>\n

      \n
    1. $lte<\/span><\/li>\n
    2. $belowEqual<\/span><\/li>\n
    3. $lessEqual<\/span><\/li>\n
    4. $maximum<\/span><\/li>\n<\/ol>\n

      Correct Answer: 1<\/b><\/p>\n

      Explanation:<\/b><\/p>\n

      The $lte operator matches values that are less than or equal to the supplied comparison value. It is useful for range queries involving numeric values, dates, and other supported comparable types. For example, an application can use $lte to find records whose timestamp falls before a deadline or whose numeric value remains below a specified limit. Indexes can improve range-query performance when the indexed field aligns with the predicate. DBAs should also consider data type consistency because comparison behavior depends on BSON value types and MongoDB’s comparison rules.<\/span><\/p>\n

      Question 163<\/b><\/h3>\n

      Which MongoDB operator checks whether a field value differs from a specified value?<\/b><\/p>\n

        \n
      1. $different<\/span><\/li>\n
      2. $ne<\/span><\/li>\n
      3. $notEqualValue<\/span><\/li>\n
      4. $excludeValue<\/span><\/li>\n<\/ol>\n

        Correct Answer: 2<\/b><\/p>\n

        Explanation:<\/b><\/p>\n

        The $ne operator matches documents where a field value is not equal to the specified value. It is useful when applications need to exclude records containing a particular value. However, negative predicates such as $ne may be less selective than equality predicates, so they do not always provide the same indexing benefits. Administrators should test such queries against realistic datasets rather than assuming an index will make every negative comparison efficient. $ne can also interact with missing fields according to MongoDB’s query semantics, so DBAs should understand how absent fields affect the intended filter.<\/span><\/p>\n

        Question 164<\/b><\/h3>\n

        Which MongoDB method retrieves one matching document?<\/b><\/p>\n

          \n
        1. findSingle()<\/span><\/li>\n
        2. findOne()<\/span><\/li>\n
        3. getDocument()<\/span><\/li>\n
        4. readOne()<\/span><\/li>\n<\/ol>\n

          Correct Answer: 2<\/b><\/p>\n

          Explanation:<\/b><\/p>\n

          findOne() returns a single document matching the supplied query condition. If several documents satisfy the filter, the method returns one matching document rather than returning the entire result set. When the application requires a predictable particular document among multiple matches, administrators should use suitable filtering and sorting behavior. findOne() is commonly used for lookups by identifiers, configuration records, or other fields expected to identify a single logical record. Indexes can improve lookup performance, especially when the filter uses a selective indexed field.<\/span><\/p>\n

          Question 165<\/b><\/h3>\n

          Which MongoDB method retrieves documents matching a query?<\/b><\/p>\n

            \n
          1. find()<\/span><\/li>\n
          2. search()<\/span><\/li>\n
          3. queryDocuments()<\/span><\/li>\n
          4. getMany()<\/span><\/li>\n<\/ol>\n

            Correct Answer: 1<\/b><\/p>\n

            Explanation:<\/b><\/p>\n

            The find() method retrieves documents that satisfy a query filter. It is one of the fundamental MongoDB read operations and can be combined with projection, sorting, pagination, and other supported query features. Efficient use of find() depends heavily on appropriate query predicates and indexes. Administrators should avoid retrieving unnecessary fields or excessive result sets when applications need only a limited subset of information. Explain plans can be used to determine how MongoDB executes frequently used find() operations and whether the available indexes align with application access patterns.<\/span><\/p>\n

            Question 166<\/b><\/h3>\n

            Which MongoDB method controls the maximum number of documents returned by a cursor?<\/b><\/p>\n

              \n
            1. restrict()<\/span><\/li>\n
            2. cap()<\/span><\/li>\n
            3. limit()<\/span><\/li>\n
            4. maximum()<\/span><\/li>\n<\/ol>\n

              Correct Answer: 3<\/b><\/p>\n

              Explanation:<\/b><\/p>\n

              The limit() cursor method restricts the number of documents returned by a query. It is useful for pagination, top-result queries, and administrative tasks where retrieving an entire result set would be unnecessary. Combining limit() with an appropriate sort and index can help applications retrieve a predictable subset efficiently. A limit does not necessarily eliminate all work required to identify matching documents, so query planning and index design remain important. DBAs should also consider whether large offsets or repeated pagination requests create unnecessary scanning and whether alternative pagination strategies are more suitable.<\/span><\/p>\n

              Question 167<\/b><\/h3>\n

              Which cursor method orders query results according to specified fields?<\/b><\/p>\n

                \n
              1. orderBy()<\/span><\/li>\n
              2. sort()<\/span><\/li>\n
              3. arrange()<\/span><\/li>\n
              4. sequence()<\/span><\/li>\n<\/ol>\n

                Correct Answer: 2<\/b><\/p>\n

                Explanation:<\/b><\/p>\n

                The sort() cursor method specifies the ordering of documents returned by a query. Sort specifications can use ascending or descending directions for selected fields. Proper index design can allow MongoDB to satisfy both filtering and sorting efficiently, reducing the need for an expensive in-memory sort. DBAs should inspect explain output when sorting large result sets, especially if the sort fields are not supported by a suitable index. Sorting behavior also interacts with result limits, pagination, and compound-index ordering, so query design should consider the complete access pattern.<\/span><\/p>\n

                Question 168<\/b><\/h3>\n

                Which MongoDB projection operator excludes a field from query results?<\/b><\/p>\n

                  \n
                1. $omit<\/span><\/li>\n
                2. $hide<\/span><\/li>\n
                3. $exclude<\/span><\/li>\n
                4. Projection exclusion<\/span><\/li>\n<\/ol>\n

                  Correct Answer: 4<\/b><\/p>\n

                  Explanation:<\/b><\/p>\n

                  Projection exclusion allows applications to specify fields that should not be returned in query results. This can reduce network traffic and prevent unnecessary fields from being exposed to application components. MongoDB projections can generally use either inclusion or exclusion semantics, with specific rules for the _id field. DBAs should ensure that application queries request only information that is required. Reducing returned document size can improve network and application efficiency, particularly when documents contain large embedded structures or fields that clients do not need.<\/span><\/p>\n

                  Question 169<\/b><\/h3>\n

                  Which MongoDB command renames an existing collection?<\/b><\/p>\n

                    \n
                  1. db.renameCollection()<\/span><\/li>\n
                  2. db.changeCollectionName()<\/span><\/li>\n
                  3. db.collection.rename()<\/span><\/li>\n
                  4. db.moveCollection()<\/span><\/li>\n<\/ol>\n

                    Correct Answer: 1<\/b><\/p>\n

                    Explanation:<\/b><\/p>\n

                    db.renameCollection() changes the name of an existing collection within MongoDB. Renaming can be useful during schema migrations, application transitions, or controlled administrative restructuring. Because applications may reference the original collection name directly, administrators should coordinate the operation with application configuration and deployment procedures. DBAs should also understand how collection-related objects and dependencies behave during renaming. A rename is different from creating a new collection and copying documents because the operation works with the existing collection rather than requiring a complete application-level data migration.<\/span><\/p>\n

                    Question 170<\/b><\/h3>\n

                    Which MongoDB command lists collections in the current database?<\/b><\/p>\n

                      \n
                    1. db.getCollectionNames()<\/span><\/li>\n
                    2. db.listCollectionsNames()<\/span><\/li>\n
                    3. db.showCollections()<\/span><\/li>\n
                    4. db.collectionNames()<\/span><\/li>\n<\/ol>\n

                      Correct Answer: 1<\/b><\/p>\n

                      Explanation:<\/b><\/p>\n

                      db.getCollectionNames() returns the names of collections in the current database. It is useful for administrative scripts, database inspection, and automation tasks that need to discover collection names dynamically. The command reports collection names rather than the full metadata associated with each collection. When detailed collection options or metadata are required, administrators can use collection-listing commands that return richer information. DBAs should verify the active database context before using the method because it operates against the currently selected database.<\/span><\/p>\n

                      Question 171<\/b><\/h3>\n

                      Which command lists detailed metadata for collections in a database?<\/b><\/p>\n

                        \n
                      1. db.collectionDetails()<\/span><\/li>\n
                      2. db.listCollections()<\/span><\/li>\n
                      3. db.describeCollections()<\/span><\/li>\n
                      4. db.collectionsInfo()<\/span><\/li>\n<\/ol>\n

                        Correct Answer: 2<\/b><\/p>\n

                        Explanation:<\/b><\/p>\n

                        db.listCollections() provides information about collections and views in the current database. Depending on the requested options, the output can include names, types, and collection configuration details. This makes the command useful for administrative scripts that need more information than a simple list of collection names. DBAs can use it to inspect collection properties, identify views, and verify database structure. It is particularly useful during migrations or automation because scripts can discover database objects dynamically instead of relying on hard-coded assumptions about collection names.<\/span><\/p>\n

                        Question 172<\/b><\/h3>\n

                        Which MongoDB command can rename a database collection through an administrative command?<\/b><\/p>\n

                          \n
                        1. db.rename()<\/span><\/li>\n
                        2. renameCollection<\/span><\/li>\n
                        3. collectionRename<\/span><\/li>\n
                        4. changeNamespace<\/span><\/li>\n<\/ol>\n

                          Correct Answer: 2<\/b><\/p>\n

                          Explanation:<\/b><\/p>\n

                          The renameCollection administrative command changes the namespace associated with a collection. It is useful when collection naming needs to change without rebuilding the entire dataset. Because collection names can be embedded in application configuration, queries, monitoring rules, and automation scripts, DBAs should coordinate renaming with dependent systems. The operation should also be evaluated against the deployment type and MongoDB version in use. Administrators should distinguish collection renaming from moving data between collections because a rename changes the collection namespace rather than requiring a document-by-document copy.<\/span><\/p>\n

                          Question 173<\/b><\/h3>\n

                          Which MongoDB operator matches values greater than or equal to a threshold?<\/b><\/p>\n

                            \n
                          1. $minimum<\/span><\/li>\n
                          2. $aboveEqual<\/span><\/li>\n
                          3. $gte<\/span><\/li>\n
                          4. $greaterEqual<\/span><\/li>\n<\/ol>\n

                            Correct Answer: 3<\/b><\/p>\n

                            Explanation:<\/b><\/p>\n

                            The $gte comparison operator matches values greater than or equal to the specified value. It is frequently used for range filtering involving numbers, timestamps, and other comparable BSON values. For example, a query can use $gte to retrieve records created on or after a particular date. When the field is indexed appropriately, range queries can often be executed efficiently. DBAs should examine both data types and index ordering when optimizing $gte queries. Combining several range conditions on different fields may require more careful compound-index design and explain-plan analysis.<\/span><\/p>\n

                            Question 174<\/b><\/h3>\n

                            Which MongoDB method returns only selected fields from matching documents?<\/b><\/p>\n

                              \n
                            1. project()<\/span><\/li>\n
                            2. selectFields()<\/span><\/li>\n
                            3. fields()<\/span><\/li>\n
                            4. include()<\/span><\/li>\n<\/ol>\n

                              Correct Answer: 1<\/b><\/p>\n

                              Explanation:<\/b><\/p>\n

                              The project() method specifies which fields should be included or excluded from query results. Projection can reduce the amount of data transmitted to clients and limit processing of fields that applications do not need. It is especially helpful when documents contain large embedded structures or numerous attributes. MongoDB has rules governing combinations of inclusion and exclusion projections, with _id receiving special treatment. DBAs should encourage applications to retrieve only required fields when practical because smaller result documents can reduce network, memory, and serialization overhead.<\/span><\/p>\n

                              Question 175<\/b><\/h3>\n

                              Which MongoDB command retrieves the first matching document while applying a sort order?<\/b><\/p>\n

                                \n
                              1. findFirst()<\/span><\/li>\n
                              2. findOne()<\/span><\/li>\n
                              3. firstDocument()<\/span><\/li>\n
                              4. getFirst()<\/span><\/li>\n<\/ol>\n

                                Correct Answer: 2<\/b><\/p>\n

                                Explanation:<\/b><\/p>\n

                                findOne() can be combined with a sort specification to select a particular document according to the desired ordering. For example, an application can use a descending timestamp sort to retrieve the newest matching record. Without an appropriate sort, when multiple documents match, the returned document should not be treated as a deterministic first result based solely on natural order. Indexes can improve these operations when they align with both the filter and sort pattern. DBAs should analyze such queries carefully when applications rely on consistently selecting the newest, oldest, or otherwise ordered matching document.<\/span><\/p>\n

                                Question 176<\/b><\/h3>\n

                                Which MongoDB operator matches array fields containing every specified value?<\/b><\/p>\n

                                  \n
                                1. $each<\/span><\/li>\n
                                2. $containsAll<\/span><\/li>\n
                                3. $all<\/span><\/li>\n
                                4. $every<\/span><\/li>\n<\/ol>\n

                                  Correct Answer: 3<\/b><\/p>\n

                                  Explanation:<\/b><\/p>\n

                                  The $all operator matches documents where an array field contains all of the specified values. It is useful for filtering records that must possess several required tags, categories, or attributes stored within an array. $all is different from $in, which succeeds when at least one supplied value matches. Administrators should understand these semantics when designing application filters because selecting the wrong operator can return an incorrect dataset. Query performance depends on the array structure and available indexes, so frequently executed array searches should be validated with realistic workloads.<\/span><\/p>\n

                                  Question 177<\/b><\/h3>\n

                                  Which MongoDB method counts matching documents in a collection?<\/b><\/p>\n

                                    \n
                                  1. countDocuments()<\/span><\/li>\n
                                  2. documentTotal()<\/span><\/li>\n
                                  3. countMatches()<\/span><\/li>\n
                                  4. recordsCount()<\/span><\/li>\n<\/ol>\n

                                    Correct Answer: 1<\/b><\/p>\n

                                    Explanation:<\/b><\/p>\n

                                    countDocuments() counts documents that match a specified query filter. It is useful when applications or administrative scripts need an accurate count for a defined condition. Query performance depends on the filter, collection size, indexes, and MongoDB execution strategy. Counting very large datasets can still require substantial processing when no efficient path is available. DBAs should therefore avoid unnecessary repeated full-collection counts in high-frequency application paths. When only an approximate collection size is needed for administrative purposes, other statistics may provide a more efficient alternative.<\/span><\/p>\n

                                    Question 178<\/b><\/h3>\n

                                    Which MongoDB command estimates collection document counts without requiring a filtered query?<\/b><\/p>\n

                                      \n
                                    1. db.collection.total()<\/span><\/li>\n
                                    2. db.collection.approximateCount()<\/span><\/li>\n
                                    3. db.collection.estimatedDocumentCount()<\/span><\/li>\n
                                    4. db.collection.fastCount()<\/span><\/li>\n<\/ol>\n

                                      Correct Answer: 3<\/b><\/p>\n

                                      Explanation:<\/b><\/p>\n

                                      estimatedDocumentCount() returns an estimated count of documents in a collection without applying a query filter. It is designed for situations where an approximate total is sufficient and can be faster than calculating an exact count over the complete dataset. It should not be confused with countDocuments(), which evaluates a filter and provides a count based on matching documents. DBAs can use estimated counts for monitoring, administrative displays, or capacity-related checks where exact precision is unnecessary. Applications requiring an exact filtered count should use an operation designed for that requirement instead.<\/span><\/p>\n

                                      Question 179<\/b><\/h3>\n

                                      Which MongoDB command retrieves the number of documents matching a filter exactly?<\/b><\/p>\n

                                        \n
                                      1. estimatedDocumentCount()<\/span><\/li>\n
                                      2. countDocuments()<\/span><\/li>\n
                                      3. approximateCount()<\/span><\/li>\n
                                      4. quickCount()<\/span><\/li>\n<\/ol>\n

                                        Correct Answer: 2<\/b><\/p>\n

                                        Explanation:<\/b><\/p>\n

                                        countDocuments() performs a count based on a specified filter, making it appropriate when an application requires the number of documents satisfying particular conditions. Unlike estimatedDocumentCount(), it does not simply provide an approximate collection-wide total. Query execution can require significant work for large datasets, particularly when the filter lacks efficient index support. DBAs should monitor applications that repeatedly perform expensive count operations and evaluate whether cached summaries, indexes, or alternative application designs are appropriate. Exact counts should be requested when their accuracy is actually required by the application.<\/span><\/p>\n

                                        Question 180<\/b><\/h3>\n

                                        Which MongoDB operation retrieves a document by its unique identifier efficiently?<\/b><\/p>\n

                                          \n
                                        1. findById()<\/span><\/li>\n
                                        2. lookupId()<\/span><\/li>\n
                                        3. findOne({_id: value})<\/span><\/li>\n
                                        4. getByIdentifier()<\/span><\/li>\n<\/ol>\n

                                          Correct Answer: 3<\/b><\/p>\n

                                          Explanation:<\/b><\/p>\n

                                          A query using findOne({_id: value}) retrieves a document by its _id field. MongoDB automatically creates a unique index on _id, allowing these lookups to be highly efficient in normal collections. The _id field serves as the primary document identifier and must be unique within a collection. Applications commonly use _id lookups when retrieving individual records after obtaining their identifiers from another operation. DBAs should preserve appropriate _id values and avoid unnecessary application-side scans when a direct identifier lookup can efficiently locate the required document.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

                                          View Full MongoDB C100DBA Exam Dumps and Practice Test Dumps   Question 161 Which MongoDB operator tests whether a field value is greater than a specified value? $above $greater $gtValue $gt Correct Answer: 4 Explanation: The $gt comparison operator matches documents where a specified field contains a value greater than the supplied comparison value. It […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1648,1647],"tags":[],"_links":{"self":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/23296"}],"collection":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/comments?post=23296"}],"version-history":[{"count":1,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/23296\/revisions"}],"predecessor-version":[{"id":23297,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/23296\/revisions\/23297"}],"wp:attachment":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/media?parent=23296"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/categories?post=23296"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/tags?post=23296"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}