Alternative to Oracle

Features

Oracle_Database -> For end user databases: Trackers. For a more traditional relational database, use the same as Tiki: MySQL (by Oracle!) or MariaDB
Oracle Secure Enterprise Search -> Elasticsearch
Beehive -> Kolab , Tiki Workspaces, Wiki, Jitsi Meet & Jitsi , File Gallery, etc.
Oracle Applications (ERP / Financials / supply-chain management, human-resource management, warehouse-management) -> This is Tiki Suite's weak spot. Please join the community to make this better! Please see: Accounting
Oracle Linux -> ClearOS

Related links
Alternative to Google Alternative to IBM Alternative to SAP Alternative to Microsoft Alternative to Zoho Alternative to Yahoo!