Advanced Database Persistence for Java

Examples & Reference Manual
 

HyperSQL (HSQLDB)

The HotRod HyperSQL adapter automatically maps known database column types to DAO Java types. In most of the cases this default Java type is well suited to handle the database values. However, when needed the default Java type of a property can be overridden by a custom type if it's provided by the developer.

Default Java Types

If a custom Java type is not specified HotRod will use the following rules to decide which Java type to use for each HyperSQL column. In yellow is the DAO property type. In parenthesis the actual object type returned by the HyperSQL JDBC driver, that on occasions may be different.

Please note that the Java types for the HyperSQL columns may vary depending on the specific version and variant of the RDBMS, the operating system where the database engine is running, and the JDBC driver version.

HyperSQL Column Type Default Java Type
TINYINT java.lang.Byte
SMALLINT java.lang.Short
INTEGER java.lang.Integer
BIGINT java.lang.Long
DECIMAL(p,s)
NUMERIC(p,s) 		If neither p or s are specified:
  • java.math.BigInteger
If s is specified and different from zero the Java type is:
  • java.math.BigDecimal
if s is not specified or specified with a value of zero:
  • if p <= 2: java.lang.Byte
  • if 2 < p <= 4: java.lang.Short
  • if 4 < p <= 9: java.lang.Integer
  • if 8 < p <= 18: java.lang.Long
  • if p > 18: java.math.BigInteger
REAL,
FLOAT,
DOUBLE 		java.lang.Double
CHAR(n),
CHARACTER(n),
VARCHAR(n),
CHARACTER VARYING(n),
CHAR VARYING(n),
LONGVARCHAR(n),
CLOB(n) 		java.lang.String
DATE java.sql.Date
TIME(n),
TIME(n) WITH TIME ZONE 		java.sql.Time
TIMESTAMP(n),
TIMESTAMP(n) WITH TIME ZONE 		java.sql.Timestamp
BINARY(n),
VARBINARY(n),
BLOB(n) 		byte[]
BOOLEAN java.lang.Boolean
OTHER java.lang.Object
<type> ARRAY java.lang.Object
INTERVAL <qualifier> java.lang.Object
BIT(n),
BIT VARYING(n) 		java.lang.Object

Custom Java Types

To override the default Java type see the reference section for the tables, views, and selects. The Example 19 - Custom DAO Property Java Types shows a case where a custom type overrides the default type. To override the default type add a <column> tag in a <table> , <view> , or <select> definition.