SQL/MX Programming Manual for Java

SQLJ Programming
HP NonStop SQL/MX Programming Manual for Java—523726-003
3-37
Optimal Data Type Mappings
Optimal Data Type Mappings
The following table shows optimal mappings between a Java data type that you specify
for a Java host variable or iterator declaration and its equivalent SQL data type.
Although Java provides conversions for combinations of data types, such as those
listed in Input Assignability on page 3-32 and in Output Assignability on page 3-35, an
SQLJ program will perform more efficiently if it uses these mappings.
Note. For better performance in OLTP environments, use the data type mappings shown in
Ta ble 3-3
. These mappings minimize the data conversions performed by SQL/MX and,
therefore, can improve the performance of your program.
Table 3-3. Optimal Data Type Mappings (page 1 of 2)
Java Wrapper Class or
Primitive Data Type
*
SQL Data Type SQL Column Description
java.lang.Byte (or byte) CHAR[ACTER],
NATIONAL
CHAR[ACTER],
NCHAR
Fixed-length character string
java.lang.Byte (or byte) CHAR[ACTER]
VARYING,
VARCHAR,
NATIONAL
CHAR[ACTER]
VARYING,
NCHAR VARYING
Variable-length character
string
java.lang.String CHAR[ACTER],
NATIONAL
CHAR[ACTER],
NCHAR
Fixed-length character string
java.lang.String CHAR[ACTER]
VARYING,
VARCHAR,
NATIONAL
CHAR[ACTER]
VARYING,
NCHAR VARYING
Variable-length character
string
java.sql.Date DATE Date in form
yyyy-mm-dd
java.sql.Time TIME Time in form
hh:mm:ss.msssss
*
The Java primitive data types, such as boolean, byte, and int, have corresponding Java wrapper classes,
which are part of the java.lang package. Java primitive data types do not support null values. For more
information, see Null Values
on page 3-29.