org.apache.flink.connector.jdbc.table

Class JdbcLookupFunction

java.lang.Object

org.apache.flink.table.functions.UserDefinedFunction

org.apache.flink.table.functions.TableFunction<Row>

org.apache.flink.connector.jdbc.table.JdbcLookupFunction

All Implemented Interfaces:

Serializable, FunctionDefinition

public class JdbcLookupFunction
extends TableFunction<Row>

A TableFunction to query fields from JDBC by keys. The query template like:

 SELECT c, d, e, f from T where a = ? and b = ?
 

Support cache the result to avoid frequent accessing to remote databases. 1.The cacheMaxSize is -1 means not use cache. 2.For real-time data, you need to set the TTL of cache.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JdbcLookupFunction.Builder Builder for a JdbcLookupFunction.

Constructor Summary

Constructors

Constructor and Description
JdbcLookupFunction(JdbcOptions options, JdbcLookupOptions lookupOptions, String[] fieldNames, TypeInformation[] fieldTypes, String[] keyNames)

Method Summary

Modifier and Type	Method and Description
static JdbcLookupFunction.Builder	builder()
void	close() Tear-down method for user-defined function.
void	eval(Object... keys)
Connection	getDbConnection()
TypeInformation<?>[]	getParameterTypes(Class<?>[] signature) Returns TypeInformation about the operands of the evaluation method with a given signature.
TypeInformation<Row>	getResultType() Returns the result type of the evaluation method.
void	open(FunctionContext context) Setup method for user-defined function.

Methods inherited from class org.apache.flink.table.functions.TableFunction

collect, getKind, getTypeInference, setCollector

Methods inherited from class org.apache.flink.table.functions.UserDefinedFunction

functionIdentifier, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.flink.table.functions.FunctionDefinition

getRequirements, isDeterministic

Constructor Detail

JdbcLookupFunction

public JdbcLookupFunction(JdbcOptions options,
                          JdbcLookupOptions lookupOptions,
                          String[] fieldNames,
                          TypeInformation[] fieldTypes,
                          String[] keyNames)

Method Detail

builder

public static JdbcLookupFunction.Builder builder()

open

public void open(FunctionContext context)
          throws Exception

Description copied from class: UserDefinedFunction

Setup method for user-defined function. It can be used for initialization work. By default, this method does nothing.

Overrides:

open in class UserDefinedFunction

Throws:

Exception

eval

public void eval(Object... keys)

close

public void close()
           throws IOException

Description copied from class: UserDefinedFunction

Tear-down method for user-defined function. It can be used for clean up work. By default, this method does nothing.

Overrides:

close in class UserDefinedFunction

Throws:

IOException

getDbConnection

@VisibleForTesting
public Connection getDbConnection()

getResultType

public TypeInformation<Row> getResultType()

Description copied from class: TableFunction

Returns the result type of the evaluation method.

Overrides:

getResultType in class TableFunction<Row>

getParameterTypes

public TypeInformation<?>[] getParameterTypes(Class<?>[] signature)

Description copied from class: TableFunction

Returns TypeInformation about the operands of the evaluation method with a given signature.

Overrides:

getParameterTypes in class TableFunction<Row>