Chapter 8 Creating J2EE Applications for BEA WebLogic
The following table provides a list of the Java data types for CMP fields used in WebLogic Server and shows how they map to the Oracle extensions for the standard SQL data types.
| Java Types for CMP Fields | Oracle Data Types |
|---|---|
| Float | NUMBER |
| Int | INTEGER |
| Long | NUMBER |
| Short | SMALLINT |
| java.lang.String | VARCHAR/VARCHAR2 |
| java.lang.Boolean | SMALLINT |
| java.lang.Byte | SMALLINT |
| java.lang.Character | SMALLINT |
| java.lang.Double | NUMBER |
| java.lang.Float | NUMBER |
| java.lang.Integer | INTEGER |
| java.lang.Long | NUMBER |
| java.lang.Short | SMALLINT |
| java.sql.Date | DATE |
| java.sql.Time | DATE |
| java.sql.Timestamp | DATE |
| java.math.BigDecimal | NUMBER |
| byte[] | RAW, LONG RAW |
| Serializable | RAW, LONG RAW |
The SQL CHAR data type should not be used for database columns that are mapped to cmp fields. This is especially important for fields that are part of the primary key, because padding blanks that are returned by the JDBC driver can cause equality comparisons to fail when they should not. Use the SQL VARCHAR data type instead of SQL CHAR.
A cmp field of type byte[] cannot be used as a primary key unless it is wrapped in a user-defined primary key class that provides meaningful equals() and hashCode() methods. This is because the byte[] class does not provide useful equals/hashCode methods.
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