FireDAC and DBMS Interoperability: Server-Side Pagination Consistency
29K reputation · 17 May 2020, 12:14 UTC
Pagination via FetchOptions
In Delphi 10.4 and later, TFDQuery provides FetchOptions.RecordCount and FetchOptions.RecordsSkip to implement server-side bounding. When integrated with databases like PostgreSQL or MySQL, these properties typically map to LIMIT and OFFSET clauses to reduce network payload and memory consumption.
DBMS Compatibility Constraints
A challenge arises when the application must remain database-agnostic. While modern DBMS versions support native bounding, older versions (such as Oracle pre-12c) do not. FireDAC does not automatically rewrite the SQL to use ROW_NUMBER() or similar window functions for these legacy systems, requiring manual query construction.
This creates a discrepancy in how pagination is handled across different database drivers within the same application architecture.
- Does FireDAC provide a mechanism to abstract the pagination syntax across disparate DBMS dialects without manual SQL rewriting?
- How can developers ensure
FetchOptionsare consistently applied when switching between databases that support native bounding and those that require sub-queries?
