Interacting with Networks and Databases - Beginning Java 7 - page 863

• int getErrorCode() returns a vendor-specific integer error code.
Normallythisvaluewillbetheactualerrorcodereturnedbytheunderlyingdata
source.
• SQLException getNextException() returnsthe SQLException in-
stancechainedtothis SQLException object(viaacallto setNextExcep-
tion(SQLException ex) ), or null when there isn't a chained exception.
• String getSQLState() returns a “SQLstate” string that provides an
X/Open or SQL:2003 error code identifying the exception.
• Iterator<Throwable> iterator() returns an iterator over the
chained SQLException s and their causes in proper order. The iterator will
beusedtoiterateovereach SQLException anditsunderlyingcause(ifany).
Youwouldnormally notcall this method, butwouldinstead usethe enhanced
for statement (discussed in Chapter 5 ), which calls iterator() , when you
need to iterate over the chain of SQLException s.
• void setNextException(SQLException sqlex) appends sqlex
to the end of the chain.
Oneormore SQLException smightoccurwhileprocessingarequest,andthecode
that throws these exceptions can add them to a chain of SQLException s by invok-
ing setNextException() .Also,an SQLException instancemightbethrownas
aresultofadifferentexception(e.g., IOException ),whichisknownasthatexcep-
tion's cause (see Chapter 3 ) .
SQLstateerrorcodesaredefinedbytheISO/ANSIandOpenGroup(X/Open)SQL
standards.Theerrorcodeisa5-characterstringconsistingofa2-characterclassvalue
followed by a 3-character subclass value. Class value “00"”indicates success, class
value “01”indicates awarning,andotherclass values normally indicate anexception.
ExamplesofSQLstateerrorcodesare00000(success)and08001(unabletoconnectto
the data source).
Thefollowingexampleshowsyouhowyoumightstructureyourapplicationtomake
a connection to a Java DB data source, perform some work, and respond to a thrown
SQLException instance:
String url = "jdbc:derby:employee;create=true";
try (Connection con = DriverManager.getConnection(url))
{
// Perform useful work. The following throw statement
simulates a
// JDBC method throwing SQLException.