org.apache.flink.connector.jdbc.dialect

Class MySQLDialect

java.lang.Object

org.apache.flink.connector.jdbc.dialect.MySQLDialect

All Implemented Interfaces:

Serializable, JdbcDialect

public class MySQLDialect
extends Object

JDBC dialect for MySQL.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MySQLDialect()

Method Summary

Modifier and Type	Method and Description
boolean	canHandle(String url) Check if this dialect instance can handle a certain jdbc url.
Optional<String>	defaultDriverName()
String	dialectName() Get the name of jdbc dialect.
String	getLimitClause(long limit) Get limit clause to limit the number of emitted row from the jdbc source.
JdbcRowConverter	getRowConverter(org.apache.flink.table.types.logical.RowType rowType) Get converter that convert jdbc object and Flink internal object each other.
Optional<String>	getUpsertStatement(String tableName, String[] fieldNames, String[] uniqueKeyFields) Mysql upsert query use DUPLICATE KEY UPDATE.
int	maxDecimalPrecision()
int	maxTimestampPrecision()
int	minDecimalPrecision()
int	minTimestampPrecision()
String	quoteIdentifier(String identifier) Quotes the identifier.
List<org.apache.flink.table.types.logical.LogicalTypeRoot>	unsupportedTypes() Defines the unsupported types for the dialect.
void	validate(org.apache.flink.table.api.TableSchema schema) Check if this dialect instance support a specific data type in table schema.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.connector.jdbc.dialect.JdbcDialect

getDeleteStatement, getInsertIntoStatement, getRowExistsStatement, getSelectFromStatement, getUpdateStatement

Constructor Detail

MySQLDialect

public MySQLDialect()

Method Detail

canHandle

public boolean canHandle(String url)

Description copied from interface: JdbcDialect

Check if this dialect instance can handle a certain jdbc url.

Parameters:

url - the jdbc url.

Returns:

True if the dialect can be applied on the given jdbc url.

getRowConverter

public JdbcRowConverter getRowConverter(org.apache.flink.table.types.logical.RowType rowType)

Description copied from interface: JdbcDialect

Get converter that convert jdbc object and Flink internal object each other.

Parameters:

rowType - the given row type

Returns:

a row converter for the database

getLimitClause

public String getLimitClause(long limit)

Description copied from interface: JdbcDialect

Get limit clause to limit the number of emitted row from the jdbc source.

Parameters:

limit - number of row to emit. The value of the parameter should be non-negative.

Returns:

the limit clause.

defaultDriverName

public Optional<String> defaultDriverName()

Returns:

the default driver class name, if user not configure the driver class name, then will use this one.

quoteIdentifier

public String quoteIdentifier(String identifier)

Description copied from interface: JdbcDialect

Quotes the identifier. This is used to put quotes around the identifier in case the column name is a reserved keyword, or in case it contains characters that require quotes (e.g. space). Default using double quotes " to quote.

getUpsertStatement

public Optional<String> getUpsertStatement(String tableName,
                                           String[] fieldNames,
                                           String[] uniqueKeyFields)

Mysql upsert query use DUPLICATE KEY UPDATE.

NOTE: It requires Mysql's primary key to be consistent with pkFields.

We don't use REPLACE INTO, if there are other fields, we can keep their previous values.

Returns:

None if dialect does not support upsert statement, the writer will degrade to the use of select + update/insert, this performance is poor.

dialectName

public String dialectName()

Description copied from interface: JdbcDialect

Get the name of jdbc dialect.

Returns:

the dialect name.

maxDecimalPrecision

public int maxDecimalPrecision()

minDecimalPrecision

public int minDecimalPrecision()

maxTimestampPrecision

public int maxTimestampPrecision()

minTimestampPrecision

public int minTimestampPrecision()

unsupportedTypes

public List<org.apache.flink.table.types.logical.LogicalTypeRoot> unsupportedTypes()

Defines the unsupported types for the dialect.

Returns:

a list of logical type roots.

validate

public void validate(org.apache.flink.table.api.TableSchema schema)
              throws org.apache.flink.table.api.ValidationException

Description copied from interface: JdbcDialect

Check if this dialect instance support a specific data type in table schema.

Specified by:

validate in interface JdbcDialect

Parameters:

schema - the table schema.

Throws:

org.apache.flink.table.api.ValidationException - in case of the table schema contains unsupported type.