fetchObject

fetchobject is a term used in programming to describe a function or method that retrieves data from a data source and returns it as an object. The concept is common in database access layers and object-relational mapping, where a row or a set of rows is converted into instances of a class rather than bare arrays or dictionaries. The exact name and behavior vary by language and framework; some libraries expose a method named fetchObject, while others provide similar functionality under different names.

In PHP's PDO extension, the method PDOStatement::fetchObject reads the next row from a result set and returns it as an instance of a specified class. If no class is provided, it returns an instance of stdClass with properties named after the columns. When a class name is supplied, properties are assigned accordingly and the class constructor is not called unless the fetch mode is set to different options.

In other contexts, fetch-like functionality appears in data-mapper patterns and ORMs, where a query result is mapped to domain objects. The mapping can be customized to use different property names, ignore unknown columns, or apply type conversion.

Common considerations include performance impact, the need to handle nulls, and security concerns such as guarding against SQL injection and ensuring proper validation of mapped data. The approach favors strong typing and encapsulation, but it may introduce overhead compared with returning simple associative structures.

See also: PDOStatement::fetchObject, fetchAll, fetch, PDO, object-relational mapping.