findByLastNameOrFirstNameString

FindByLastName is a conventional name used for a data access query method designed to retrieve records whose lastName field matches a specified value. It is commonly used in repository patterns and ORM libraries where query methods are derived from method names. When called, it returns the matching records, which may be a single entity, a list, or an optional value depending on the framework and whether the last name is guaranteed unique.

In frameworks like Spring Data (Java), the method signature findByLastName(String lastName) instructs the framework to generate a query that matches the lastName field exactly. Variants include findByLastNameIgnoreCase, findByLastNameContaining, and findAllByLastName to accommodate case-insensitive or partial matches.

In other ecosystems, similar conventions exist: Ruby on Rails uses find_by_last_name or where(last_name: value); Django uses filter(last_name=value). Despite differences, the core idea is the same: derive a query from a method name or a DSL.

Key considerations: ensure last_name is indexed for performance; consider normalization for case-insensitive comparisons; handle nulls; understand whether multiple records can share a last name and adjust return type accordingly; beware potential performance issues with large datasets.

Common pitfalls: ambiguity when last name is not unique; inconsistent data formats; not handling locale-specific case folding.