public interface SQLData
SQLData
interface will be entered in the appropriate Connection
object's type map along with the SQL name of the UDT for which it is a custom mapping. Typically, a SQLData
implementation will define a field for each attribute of an SQL structured type or a single field for an SQL DISTINCT
type. When the UDT is retrieved from a data source with the ResultSet.getObject
method, it will be mapped as an instance of this class. A programmer can operate on this class instance just as on any other object in the Java programming language and then store any changes made to it by calling the PreparedStatement.setObject
method, which will map it back to the SQL type.
It is expected that the implementation of the class for a custom mapping will be done by a tool. In a typical implementation, the programmer would simply supply the name of the SQL UDT, the name of the class to which it is being mapped, and the names of the fields to which each of the attributes of the UDT is to be mapped. The tool will use this information to implement the SQLData.readSQL
and SQLData.writeSQL
methods. The readSQL
method calls the appropriate SQLInput
methods to read each attribute from an SQLInput
object, and the writeSQL
method calls SQLOutput
methods to write each attribute back to the data source via an SQLOutput
object.
An application programmer will not normally call SQLData
methods directly, and the SQLInput
and SQLOutput
methods are called internally by SQLData
methods, not by application code.
Modifier and Type | Method | Description |
---|---|---|
String |
getSQLTypeName() |
Returns the fully-qualified name of the SQL user-defined type that this object represents. |
void |
readSQL |
Populates this object with data read from the database. |
void |
writeSQL |
Writes this object to the given SQL data stream, converting it back to its SQL value in the data source. |
String getSQLTypeName() throws SQLException
SQLData
.readSQL
when this object was constructed and populatedSQLException
- if there is a database access errorSQLFeatureNotSupportedException
- if the JDBC driver does not support this methodvoid readSQL(SQLInput stream, String typeName) throws SQLException
readSQL
then assigns the data to appropriate fields or elements (of this or other objects). Specifically, it must call the appropriate reader method (SQLInput.readString
, SQLInput.readBigDecimal
, and so on) method(s) to do the following: for a distinct type, read its single data element; for a structured type, read a value for each attribute of the SQL type. SQLInput
reader method on the stream.stream
- the SQLInput
object from which to read the data for the value that is being custom mappedtypeName
- the SQL type name of the value on the data streamSQLException
- if there is a database access errorSQLFeatureNotSupportedException
- if the JDBC driver does not support this methodvoid writeSQL(SQLOutput stream) throws SQLException
SQLOutput
writer method(s) (writeInt
, writeString
, and so on) to do the following: for a Distinct Type, write its single data element; for a Structured Type, write a value for each attribute of the SQL type.stream
- the SQLOutput
object to which to write the data for the value that was custom mappedSQLException
- if there is a database access errorSQLFeatureNotSupportedException
- if the JDBC driver does not support this method
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https://docs.oracle.com/en/java/javase/21/docs/api/java.sql/java/sql/SQLData.html