Review these topics to determine which is the best path for you to select to upgrade Oracle Databases.

• Overview of Converting Databases During Upgrades
  There are four methods you can use to convert databases during Oracle Database upgrades.
• About 32-bit Oracle Databases to 64-bit Oracle Database Conversions
  32-bit Oracle Databases are automatically converted to 64-bit.
• About Upgrading Using Standby Databases
  You can perform rolling upgrades of databases using physical standbys, Oracle Data Guard, or Oracle Enterprise Manager Cloud Control.
• Using Oracle GoldenGate for Online Database Upgrades
  The continuous extraction and replication capabilities of Oracle GoldenGate can enable online upgrades of Oracle Database.
• Software-Only Manual Upgrades Using DDLs
  If you perform a software-only non-CDB installation, without creating a database, and instead use DDL statements to create a database, then special considerations apply for Oracle Database 12c Release 2 (12.2).
• Migrating From Standard Edition to Enterprise Edition of Oracle Database
  Review these options to migrate to Oracle Database Enterprise Edition from Oracle Database Standard Edition
• Migrating from Enterprise Edition to Standard Edition of Oracle Database
  Converting from Enterprise Edition to Standard Edition requires exporting and importing data.
• Migrating from Oracle Database Express Edition (Oracle Database XE) to Oracle Database
  You must upgrade from Oracle Database Express Edition to Oracle Database Enterprise Edition, and then upgrade to the current Oracle Database release.