Advanced Database Persistence for Java

Examples & Reference Manual
 

Microsoft SQL Server

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

Please note that the Java types for the SQL Server 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.

SQL Server Column Type Default Java Type
BIT java.lang.Byte
TINYINT java.lang.Byte
SMALLINT java.lang.Short
INT java.lang.Integer
BIGINT java.lang.Long
DECIMAL(p,s),
DEC(p,s),
NUMERIC(p,s) 		If neither p or s are specified, i.e. DECIMAL(18,0):
  • java.lang.Long
If s is specified and different from zero the Java type is:
  • java.math.BigDecimal
if s is not specified or it's 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
MONEY,
SMALLMONEY 		java.math.BigDecimal
FLOAT(n) If n is not specified, i.e. a FLOAT(53):
  • java.lang.Double
if n is specified:
  • if n <= 24: java.lang.Float
  • if n >= 25: java.lang.Double
REAL java.lang.Float
Note: REAL is equivalent to FLOAT(24),
CHAR(n),
CHARACTER(n),
VARCHAR(n|MAX),
CHARVARYING(n|MAX),
CHARACTERVARYING(n|MAX),
NCHAR(n),
NATIONAL CHAR(n),
NATIONAL CHARACTER(n),
NVARCHAR(n|MAX),
NATIONAL CHAR VARYING(n|MAX),
NATIONAL CHARACTER VARYING(n|MAX),
TEXT,
NTEXT 		java.lang.String
DATE java.sql.Date
DATETIME,
SMALLDATETIME 		java.util.Date
DATETIME2(n),
DATETIMEOFFSET(n) 		java.sql.Timestamp
TIME(n) If n is not specified, i.e. TIME(7):
  • java.sql.Timestamp
If n is specified:
  • If n <=3: java.sql.Time
  • If n >=4: java.sql.Timestamp
BINARY(n),
VARBINARY(n|MAX),
IMAGE 		byte[]
HIERARCHYID byte[]
ROWVERSION java.lang.Object Cannot insert, nor update by PK. Selects and deletes work normally. Rows can be “updated by example” when excluding this column.
UNIQUEIDENTIFIER java.lang.String
SQL_VARIANT This type is not supported by the JDBC driver 4.0 provided by SQL Server. A workaround, at least to read it, is to cast this column to a different supported type (maybe using a view or a select) as in th expression: CAST(<column> AS <type>)
XML java.lang.String *
GEOGRAPHY byte[] **
GEOMETRY byte[] **
(pseudo column) <col> as <expression> Type depends on expression type. Cannot insert, nor update by PK. Selects and deletes work normally. Rows can be “updated by example” when excluding this column.

* Must be a well-formed XML String. Depending on the column definition it may also need to be a valid XML String.
** These data types represent well-formed binary data as specified by the “[MS-SSCLRT]: Microsoft SQL Server CLR Types Serialization Formats” document at https://msdn.microsoft.com/en-us/library/ee320529.aspx .

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.