Java Reference
In-Depth Information
tem.out.println(rsSchem.getString("TABLE_SCHEM"));
System.out.println();
System.out.println("Schema/Table");
System.out.println("------------");
rsSchem = dbmd.getSchemas();
while (rsSchem.next())
{
String schem = rsSchem.getString("TABLE_SCHEM");
ResultSet rsTab = dbmd.getTables(null, schem, "%",
null);
while (rsTab.next())
System.out.println(schem+"
"+r-
sTab.getString("TABLE_NAME"));
}
}
}
output assorted metadata.
The
int getDatabaseMajorVersion()
and
int getData-
baseMinorVersion()
methodsreturnthemajor(e.g.,10)andminor(e.g.,8)parts
ofJavaDB'sversionnumber.Similarly,
String getDatabaseProductName()
returns the name of this product (e.g., Apache Derby), and
String getDriver-
Name()
returns the name of the driver (e.g., Apache Derby Embedded JDBC Driver).
SQL defines various functions that can be invoked as part of
SELECT
and other
statements. For example, you can specify
SELECT COUNT(*) AS TOTAL FROM
EMPLOYEES
to return a one-row-by-one-column result set with the column named
TOTAL
and the row value containing the number of rows in the
EMPLOYEES
table.
BecausenotallRDMSesadoptthesamesyntaxforspecifyingfunctioncalls,JDBC
uses a
function escape clause
, consisting of
{ fn
functionname
(
arguments
)
}
,toabstractoverdifferences.Forexample,
SELECT {fn UCASE(NAME)} FROM
EMPLOYEES
selects all
NAME
column values from
EMPLOYEES
and uppercases their
values in the result set.
The
String getNumericFunctions()
,
String getStringFunc-
tions()
,
String getSystemFunctions()
, and
String
getTimeDateFunctions()
methodsreturnlistsoffunctionnamesthatcanappear
