Throw an exception in case a statement using ReturningMode.SINGLE produces more than 1 result.

What a returning single statement does when the database answers with more than one row. Off, the first row is returned and the rest are dropped; on, it throws.

A statement declared single is a claim that at most one row can match. Where that claim rests on a unique constraint the database enforces, the check is redundant and the default is right. Where it rests on you being sure — a lookup by something that ought to be unique but is not constrained to be — turning this on converts a silent wrong answer into a loud one.

It costs nothing at run time beyond reading one more row.

Configuration Options

Option: ‘false’

The default. A second row is ignored:

public final class TenantRepository {

    public Optional<Tenant> findTenantBySlug(final String slug) {
        // ... reads every row, answers with the first
    }

}

Option: ’true'

A second row is a defect, and says so:

public final class TenantRepository {

    public Optional<Tenant> findTenantBySlug(final String slug) {
        // ... throws when the statement answers with more than one row
    }

}

Related Options

Also in this group: annotations , catchAndRethrow , createConnection , description , executeBatch , executeOnce , generateConnectionOverloads , generateResultRowType , injectConverter , name , parameters , repository , resultRowColumns , resultRowConverter , resultRowType , returningMode , type , validateSchema , vendor , writesReturnUpdateCount .

Front Matter

In order to configure this option, place the following code in the front matter of your SQL statement:

-- throwOnMultipleResults: true
SELECT  something
FROM    your_database_schema
WHERE   some_column = :some_value