Jaybird 2.1 JDBC driver Java Programmer's Manual - Firebird

tables using the above mentioned method.
Statement stmt = connection.createStatement();
try {
DatabaseMetaData metaData = connection.getMetaData();
ResultSet tables = metaData.getTables(
null, null, "customer", new String[]{"TABLE"});
if (!tables.next())
stmt.execute("CREATE TABLE customer(" +
"customerId INTEGER NOT NULL PRIMARY KEY, " +
"firstName VARCHAR(20) NOT NULL, " +
"lastName VARCHAR(40) NOT NULL)");
} finally {
stmt.close();
}
Illustration 4.3: Example of creating database tables.
First, application checks the existence of the table in the database by calling the
DatabaseMetaData.getTables(String, String, String, String[])
method that returns a result set describing the database tables matching the
specified search pattern. First two parameters of this method, the database catalog
and schema names, are set to null as Firebird supports neither catalogs nor
schemas. Third parameter is the table name search pattern, in our case we search
for the table "customer". Last parameter is the list of table types to check, in our
case we check for the "TABLE" type. Other tables types are "SYSTEM TABLE" and
"VIEW".
After that application checks if the result set is empty by calling the
ResultSet.next() method. If no "customer" table was found, application
creates new table with three columns.
As it was already mentioned, the Statement.execute(String) method can also
be used to execute statements of the unknown type.
Statement stmt = connection.createStatement();
try {
boolean hasResultSet = stmt.execute(sql);
if (hasResultSet) {
ResultSet rs = stmt.getResultSet();
...
} else {
int updateCount = stmt.getUpdateCount();
...
}
} finally {
stmt.close();
}
It is worth mentioning, that according to the JDBC specification getResultSet()
and getUpdateCount() methods can be only called once per result, and in case of
using Firebird, that means once per executed statement, since Firebird does not
support multiple results from a single statement. Calling the methods the second
time will cause an exception.
Chapter 4. Executing statements 36