How to Efficiently Check for Results in a Java ResultSet?

Checking for Results in Java ResultSet

When working with JDBC's ResultSet object, it is often necessary to determine if there are any results available. Unlike many other iterator-based collections in Java, ResultSet lacks a hasNext() method.

Standard Approach

A common approach is to use the next() method. However, this requires the cursor to be advanced, potentially causing issues if the data is to be read later.

if (!resultSet.next()) {
    System.out.println("No data");
}

Alternative Method: isBeforeFirst()

A more efficient alternative is to use the isBeforeFirst() method, which checks if the cursor is not before the first record or if there are no rows in the ResultSet.

if (!resultSet.isBeforeFirst()) {
    System.out.println("No data");
}

This approach avoids having to advance the cursor and ensures that the data can be read as expected. Therefore, it is recommended to use isBeforeFirst() when checking for the presence of results in a Java ResultSet.

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