Advanced Database Persistence for Java

Examples & Reference Manual
 

Oracle

The HotRod Oracle 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 Oracle column. In yellow is the DAO property type. In parenthesis the actual object type returned by the Oracle JDBC driver, that on occasions may be different.

Please note that the Java types for the Oracle 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.

Oracle Column Type Default Java Type
NUMBER(p,s),
DECIMAL(p,s),
DEC(p,s),
NUMERIC(p,s),
NUM(p,s) 		If neither p or s are specified:
  • java.math.BigDecimal
If both are specified and s is different from zero the Java type is:
  • java.math.BigDecimal
if p is specified and 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
SMALLINT,
INTEGER,
INT 		java.math.BigInteger
Note: SMALLINT, INTEGER, and INT are equivalent to NUMBER(38).
FLOAT(p) if p is not specified (i.e. a 126-bit float):
  • java.math.BigDecimal
if p is specified:
  • if p <= 23: java.lang.Float
  • if 24 <= p <= 52: java.lang.Double
  • if p >=53: java.math.BigDecimal
REAL java.math.BigDecimal
Note: REAL is equivalent to FLOAT(63).
DOUBLE PRECISION java.math.BigDecimal
Note: DOUBLE PRECISION is equivalent to FLOAT(126).
BINARY_FLOAT java.lang.Float
BINARY_DOUBLE java.lang.Double
CHAR(n),
VARCHAR(n),
VARCHAR2(n),
NCHAR(n),
NVARCHAR2(n) 		java.lang.String
CLOB,
NCLOB 		java.lang.String *
LONG No default java type **
RAW(n),
LONG RAW 		byte[]
BLOB byte[] *
BFILE No default java type **
DATE java.util.Date
TIMESTAMP java.sql.Timestamp
TIMESTAMP WITH TIME ZONE java.sql.Timestamp
TIMESTAMP WITH LOCAL TIME ZONE java.sql.Timestamp
ROWID java.lang.String
UROWID java.lang.Object (oracle.sql.ROWID)
XMLTYPE No default java type **
URITYPE java.lang.Object (oracle.sql.STRUCT)
INTERVAL YEAR TO MONTH java.lang.Object (oracle.sql.INTERVALYM)
INTERVAL DAY TO SECOND java.lang.Object (oracle.sql.INTERVALDS)
VARRAY(n) java.lang.Object (oracle.sql.ARRAY)
STRUCT java.lang.Object (oracle.sql.STRUCT)
REF java.lang.Object

* LOB types are by default read all at once into memory as byte arrays. They can also be read/written using streaming instead of loading them all at once. To do this you’ll need to write a custom MyBatis TypeHandler .

** It may be possible to read/write from/to these columns using a MyBatis custom TypeHandler . This is, however, not an out-of-the-box solution.

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.