Hi,
Please correct me, to my knowledge,
1. when CRM is installed, two DB are created. i) MSCRM_DB ii) OrganizationName_DB.
MSCRM_DB - stores license key information and other relevant information related to CRM.
OrganizationName_DB - store records, views, store procedures etc.
2. Two are are created @ backgrund, i) _base table - which holds OOTB fields and ii) _extensionBase table - which holds customize fields.
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