resultset

ResultSet is an interface in the Java Database Connectivity (JDBC) API that represents the data returned by executing a SQL query. It presents data as a table of rows and columns and maintains a cursor for navigating the rows.

A ResultSet is produced by executing a Statement or PreparedStatement with executeQuery. By default most drivers provide a forward-only ResultSet, but can be created as scrollable (TYPE_SCROLL_INSENSITIVE or TYPE_SCROLL_SENSITIVE) and with different concurrency modes such as CONCUR_READ_ONLY or CONCUR_UPDATABLE.

Data is accessed through getter methods like getInt, getString, or getObject, using either a 1-based column index or a column label. The wasNull method indicates whether the last read value was SQL NULL. ResultSetMetaData describes column count, names, labels, and data types.

If the ResultSet is updatable, it supports updateRow, insertRow, deleteRow, and moveToInsertRow; otherwise it is read-only. The cursor can be moved with next, and for scrollable results, absolute, relative, and other navigation methods are available.

Resource management: ResultSet should be closed when no longer needed to free database resources. It is typically closed automatically when its Statement or Connection is closed, and it is common to use try-with-resources to ensure proper closure.

Limitations and portability: feature support depends on the database and driver; some features such as scrollability and updatability may be not supported. In practice, results can be large, so developers may prefer pagination.