Pass the MongoDB Certified DBA Associate C100DBA Questions and answers with Dumpstech

The operation must update every matching document and use the $inc update operator with correct syntax. updateMany() applies the update to all documents matching { color: " green " }. The $inc operator must be the top-level update operator and receive a field-to-amount mapping, so the valid update document is { $inc: { price: 5 } }. Option C satisfies both requirements. The sweater price increases from 20 to 25, and the hat price increases from 12 to 17. Option B uses a syntactically correct $inc expression, but the legacy update() call shown does not explicitly request a multi-document update, so it does not meet the stated requirement to modify all green products. Options A and D place $inc beneath the price field instead of placing $inc at the update-operator level, which is not valid update syntax. $inc operates atomically on each affected document and can be used with positive or negative numeric increments. Therefore, the correct multi-document update is db.products.updateMany({color: " green " }, {$inc:{price:5}}), making C correct.

Study Guide reference/topic:MongoDB Architecture and Core Operations - updateMany(), update operators, filters, and $inc.

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The proposed index is a compound index across home_score and away_score. MongoDB supports compound multikey indexes, but it imposes an important restriction: for any one indexed document, no more than one field covered by the compound index may contain an array. Document 1 is valid because only away_score is an array. Document 2 is also valid because only home_score is an array. Document 4 contains scalar values for both fields. Document 3 contains arrays in both indexed fields: home_score: [5,8] and away_score: [9,6] . Indexing that document would require a compound multikey index to expand two independent array dimensions, which MongoDB prohibits. Therefore document 3 prevents the compound index from being valid. The restriction is important because a single multikey field already creates multiple index keys per document; allowing multiple independently array-valued keys in the same compound index would create ambiguous and potentially combinatorial key combinations. DBAs designing indexes over document schemas with arrays must understand these multikey constraints before building compound indexes. The failing document is _id:3, making option D correct.

Study Guide reference/topic:Indexing and Query Optimization - multikey indexes, compound multikey restrictions, and array-valued fields.

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MongoDB Enterprise auditing supports three standard destination values for audit events: syslog, file, and console. With the syslog destination, audit records are sent to the operating system ' s syslog facility where supported. With the file destination, events are written to a configured audit log path, and administrators can control the output format according to the supported audit configuration. With the console destination, audit events are emitted to standard output, which can be useful in containerized or centrally collected logging environments. A raw TCP/IP port is not itself an auditLog.destination value. Organizations can certainly forward logs over the network using operating-system or observability tooling, but that transport is external to MongoDB ' s destination setting. A MongoDB database is likewise not one of the supported audit destinations; keeping audit evidence independent from the system being audited is also preferable for integrity and compliance. Auditing records security-relevant actions and can be filtered to meet regulatory or operational requirements. Therefore the three valid destinations among the choices are syslog, file, and console: A, B, and E.

Study Guide reference/topic:Security, Networking, and Encryption - auditing, auditLog.destination, compliance logging, and audit configuration.

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