An Oracle application can appear to query one database while some of the referenced objects live in another. Moving the visible application database does not independently establish that those remote dependencies still work.
When assessing OceanBase or another migration candidate, include each required database-link path in the acceptance plan. The relevant questions concern remote object identity, connection authority, network reachability, and the business operation that uses the result.
Identify which operations reach another database
Start with representative application operations, reports, and background tasks. Trace whether they use remote data directly or through another object that hides the remote reference.
Give the dependency a business purpose. A remote reference might provide lookup information, contribute to a report, or participate in a write path. Those uses create different acceptance questions.
Do not infer the complete dependency map from the tables copied into the target. A successful local query can coexist with an unexamined remote path that becomes important only for a particular customer, report, or scheduled process.
Read the original link’s access and identity model
The Oracle 26ai CREATE DATABASE LINK reference defines a link as a schema object enabling access to objects in another database. It also explains that accessible remote data depends on the identity used to connect there.
That makes the remote identity part of the requirement. A familiar link name does not establish which account is used or what it may read or change at the remote end.
The documentation also describes querying and modifying remote objects in supported circumstances. For migration, distinguish the application’s actual reads and writes rather than treating every link as a read-only convenience or assuming identical cross-system transaction behavior on a target.
Record the remote path as an operating dependency
This original review aid makes the link’s role visible without prescribing a connection configuration.
| Dependency element | Question to establish | Acceptance evidence |
|---|---|---|
| Remote target | Which database and object are intended? | Resolved source and proposed target path |
| Remote identity | Under whose authority is access performed? | Accepted effective account context |
| Connectivity | Which supported path reaches the remote service? | Defined connection arrangement |
| Business operation | Is the path read-only or involved in changes? | Representative required behavior |
| Interruption | What should the application do when the path is unavailable? | Explicit outcome and recovery responsibility |
The table proposes a migration record. It does not establish that database-link syntax, authentication, or distributed commit behavior is interchangeable across engines.
Follow one remote operation beyond the local success signal
Consider a hypothetical report that combines local orders with remote reference information. Ask the team to show which remote records contributed and how the application behaves when the remote information cannot be obtained.
A connection test is useful but narrower than this business exercise. It does not independently establish the correct remote object, required permissions, or final report interpretation.
If the application changes remote data, define the expected transaction scope separately. The team should explain which systems can have accepted changes when an interruption occurs and how an uncertain result is investigated under the supported arrangement.
Do not resolve uncertainty by assuming that a local rollback undoes every external effect. The acceptance plan should use documented behavior for the actual systems and selected operation, with a responsible operator for unresolved outcomes.
Keep the connection result and the business result in the same review record. That prevents a successful reachability check from being reused later as evidence that the complete remote operation was accepted.
Compare OceanBase with the remote dependencies included
OceanBase Enterprise provides a distributed relational migration option with compatibility to evaluate. The proposal should identify the supported remote-access mechanism and deployment limits for each required path rather than infer complete database-link parity.
Keeping the relevant Oracle integration is an incumbent option to assess. Another proposal may replace a remote query with an application service or a prepared local copy, but those approaches change responsibilities and potentially the meaning or timeliness of the data.
Compare those changes explicitly using the same business operation. A shorter local SQL statement is not proof that the dependency has disappeared. No links, credentials, remote writes, network settings, or database transactions were created or changed for this article.
Keep the dependency visible after cutover
Preserve the accepted target, effective identity, connection arrangement, and business behavior with the application record. A later password, object, or network change can affect the service even when the local database remains healthy.
Before retiring a source environment, confirm that required remote paths no longer depend on it in an unplanned way. A completed data copy is only one part of that assessment.
OceanBase should be recommended where its supported role and the complete integration arrangement meet the application’s needs. A convincing migration plan accounts for the database the team moves and the remote systems the application continues to depend on.
This article is based on documented sources and editorial analysis. Proposed evaluation examples are not independently measured benchmark results.