Revision as of 03:05, 24 November 2010

CORA and the CMDB

Brief Overview of CORA

In an effort to combine multiple products into one database, CA developed a Common Register API or CORA. CORA is the logic that determines if an asset/CI is new to the database or preexisting record.

The Master Asset Data Model defines how CI’s and Assets are loaded into the MDB

There are three levels to the model; source, logical and physical.

Source Tracks how the asset was loaded

• ca_asset_source table

Logical Stores virtual assets (this is per CA’s definition but I have found ALL assets are stored in this table.)

• ca_logical_asset and ca_logical_asset_property tables

Physical Stores data to help identify an asset as being unique to the database

• ca_asset table

As you can see the ca_owned_resource table is missing from this list. Keep this in mind when loading data since a record may not exist in Service Desk but it can be located elsewhere in the MDB. If you create a new record in Service Desk and then load the same record from an outside source such as Cohesion or Advantage Data Transformer you may end up with a duplicate record. To avoid this you need to utilize the Black Box Fields Preventing data duplication by using Black Box Fields When loading data into the CMDB it is important to avoid record duplication, the best way to avoid duplication is by following this rule; “Blanks are Good.” This means that the source file should contain only one or two Black Box Fields; the record in this field must match exactly what is currently in the CMDB. No extra spaces, commas, apostrophes, dashes, etc. if it does CORA may see it as unique and load it as a new record thus creating a duplicate of an existing record. Therefore, less is better, the less fields CORA has to look at the less likely there will be duplicated data.

The CORA looks at six fields to determine if a record is new or a duplicate. These fields are referred to as Black Box Fields and are listed below in order of importance. (The field from Webscreen Painter is in parenthesis)

 1)  Serial Number (serial_number) is the most important field. CORA will always match two assets with the same serial number unless Asset Tag or Host Name is different. 
 2)  Asset Tag  (asset_num) is the second most highly weighted field. Serial Number and Alt Asset ID appear at the highest level of the Asset Registration schema in the ca_asset table. 
 3)  Host Name (system_name) if Serial Number and Alt Asset ID are blank the Host Name takes precedence over DNS and MAC Address values. Although more than one DNS/MAC pair can be specified for the same Host Name, it will still be considered the same Asset.   This field is also a key field in the ca_logical_asset table. 
 4)  DNS Name (dns_name) and (5) MAC Address (mac_address) are weighted the same. CORA will recognize the same asset if DNS or MAC address match and will create a new asset when they do not. 
 6)  Asset Label (name) is required to create an asset, you can have multiple assets with the same name, but all of the other CORA fields cannot match or need to be empty. 

CORA recognizes a duplicate based on these values alone so they must match exactly what is currently in the database to prevent duplication.

The table below is from CA’s CORA_MDB_Assets_SC.pdf and gives an example of how the CORA determines if a record is new or existing. In the table they refer to it as a duplicate, what they mean is that it is pre-existing in the database and will not be created new, not that it will be duplicated.