5.2.2. Basic value types

The built-in basic mapping types can be roughly categorized into the following:
integer, long, short, float, double, character, byte, boolean, yes_no, true_false
Type mappings from Java primitives or wrapper classes to appropriate (vendor-specific) SQL column types. boolean, yes_no and true_false are all alternative encodings for a Java boolean or java.lang.Boolean.
A type mapping from java.lang.String to VARCHAR (or Oracle VARCHAR2).
date, time, timestamp
Type mappings from java.util.Date and its subclasses to SQL types DATE, TIME and TIMESTAMP (or equivalent).
calendar, calendar_date
Type mappings from java.util.Calendar to SQL types TIMESTAMP and DATE (or equivalent).
big_decimal, big_integer
Type mappings from java.math.BigDecimal and java.math.BigInteger to NUMERIC (or Oracle NUMBER).
locale, timezone, currency
Type mappings from java.util.Locale, java.util.TimeZone and java.util.Currency to VARCHAR (or Oracle VARCHAR2). Instances of Locale and Currency are mapped to their ISO codes. Instances of TimeZone are mapped to their ID.
A type mapping from java.lang.Class to VARCHAR (or Oracle VARCHAR2). A Class is mapped to its fully qualified name.
Maps byte arrays to an appropriate SQL binary type.
Maps long Java strings to a SQL CLOB or TEXT type.
Maps serializable Java types to an appropriate SQL binary type. You can also indicate the Hibernate type serializable with the name of a serializable Java class or interface that does not default to a basic type.
clob, blob
Type mappings for the JDBC classes java.sql.Clob and java.sql.Blob. These types can be inconvenient for some applications, since the blob or clob object cannot be reused outside of a transaction. Driver support is patchy and inconsistent.
imm_date, imm_time, imm_timestamp, imm_calendar, imm_calendar_date, imm_serializable, imm_binary
Type mappings for what are considered mutable Java types. This is where Hibernate makes certain optimizations appropriate only for immutable Java types, and the application treats the object as immutable. For example, you should not call Date.setTime() for an instance mapped as imm_timestamp. To change the value of the property, and have that change made persistent, the application must assign a new, nonidentical, object to the property.
Unique identifiers of entities and collections can be of any basic type except binary, blob and clob. Composite identifiers are also allowed. See below for more information.
The basic value types have corresponding Type constants defined on org.hibernate.Hibernate. For example, Hibernate.STRING represents the string type.