SNOW-CSA Database Administration and CMDB Practice Question
Exhibit
Discovery probe output:
{
"ip": "10.0.0.1",
"class": "Network Gear",
"name": "switch-01",
"attributes": {
"snmp_location": "DataCenter A",
"model_id": "Cisco Catalyst 3850"
}
}Refer to the exhibit. An administrator runs Discovery on a switch and receives this payload. However, the CI is not created in the CMDB. The Discovery log shows 'Identification rule did not match any CI. Creating new CI failed because of duplicate serial number?'. What is the most likely cause?
⚠ Common exam trap
ServiceNow often tests the distinction between identification rule failures (which produce 'no match' or 'multiple match' errors) and database constraint violations (like duplicate serial numbers), leading candidates to incorrectly blame the identification rule configuration when the real issue is a unique key conflict.
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
✓
There is already a CI with the same serial number.
The error message 'Creating new CI failed because of duplicate serial number' directly indicates that a CI with the same serial number already exists in the CMDB. ServiceNow enforces uniqueness on the serial number field for hardware CIs; when Discovery attempts to create a new CI but finds a matching serial number, the operation fails. This is why option B is correct.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The class 'Network Gear' is invalid.
Why it's wrong here
Invalid class would cause a different error, not a duplicate serial.
- ✓
There is already a CI with the same serial number.
Why this is correct
The log explicitly states 'duplicate serial number', indicating a serial conflict.
- ✗
The identification rule is misconfigured.
Why it's wrong here
Misconfiguration might cause no match, but the duplicate serial error is specific to serial number uniqueness.
- ✗
The serial number field is missing from the payload.
Why it's wrong here
Missing serial number would cause a different issue, not a duplicate error.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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