Source code for pyflink.table.statement_set
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from typing import Union
from pyflink.table import ExplainDetail
from pyflink.table.table_descriptor import TableDescriptor
from pyflink.table.table_result import TableResult
from pyflink.util.java_utils import to_j_explain_detail_arr
__all__ = ['StatementSet']
class StatementSet(object):
"""
A :class:`~StatementSet` accepts pipelines defined by DML statements or :class:`~Table` objects.
The planner can optimize all added statements together and then submit them as one job.
The added statements will be cleared when calling the :func:`~StatementSet.execute` method.
.. versionadded:: 1.11.0
"""
def __init__(self, _j_statement_set, t_env):
self._j_statement_set = _j_statement_set
self._t_env = t_env
[docs] def add_insert_sql(self, stmt: str) -> 'StatementSet':
"""
add insert statement to the set.
:param stmt: The statement to be added.
:return: current StatementSet instance.
.. versionadded:: 1.11.0
"""
self._j_statement_set.addInsertSql(stmt)
return self
[docs] def attach_as_datastream(self):
"""
Optimizes all statements as one entity and adds them as transformations to the underlying
StreamExecutionEnvironment.
Use :func:`~pyflink.datastream.StreamExecutionEnvironment.execute` to execute them.
The added statements will be cleared after calling this method.
.. versionadded:: 1.16.0
"""
self._j_statement_set.attachAsDataStream()
[docs] def add_insert(self,
target_path_or_descriptor: Union[str, TableDescriptor],
table,
overwrite: bool = False) -> 'StatementSet':
"""
Adds a statement that the pipeline defined by the given Table object should be written to a
table (backed by a DynamicTableSink) that was registered under the specified path or
expressed via the given TableDescriptor.
1. When target_path_or_descriptor is a tale path:
See the documentation of :func:`~TableEnvironment.use_database` or
:func:`~TableEnvironment.use_catalog` for the rules on the path resolution.
2. When target_path_or_descriptor is a table descriptor:
The given TableDescriptor is registered as an inline (i.e. anonymous) temporary catalog
table (see :func:`~TableEnvironment.create_temporary_table`).
Then a statement is added to the statement set that inserts the Table object's pipeline
into that temporary table.
This method allows to declare a Schema for the sink descriptor. The declaration is
similar to a {@code CREATE TABLE} DDL in SQL and allows to:
1. overwrite automatically derived columns with a custom DataType
2. add metadata columns next to the physical columns
3. declare a primary key
It is possible to declare a schema without physical/regular columns. In this case, those
columns will be automatically derived and implicitly put at the beginning of the schema
declaration.
Examples:
::
>>> stmt_set = table_env.create_statement_set()
>>> source_table = table_env.from_path("SourceTable")
>>> sink_descriptor = TableDescriptor.for_connector("blackhole") \\
... .schema(Schema.new_builder()
... .build()) \\
... .build()
>>> stmt_set.add_insert(sink_descriptor, source_table)
.. note:: add_insert for a table descriptor (case 2.) was added from
flink 1.14.0.
:param target_path_or_descriptor: The path of the registered
:class:`~pyflink.table.TableSink` or the descriptor describing the sink table into which
data should be inserted to which the :class:`~pyflink.table.Table` is written.
:param table: The Table to add.
:type table: pyflink.table.Table
:param overwrite: Indicates whether the insert should overwrite existing data or not.
:return: current StatementSet instance.
.. versionadded:: 1.11.0
"""
if isinstance(target_path_or_descriptor, str):
self._j_statement_set.addInsert(target_path_or_descriptor, table._j_table, overwrite)
else:
self._j_statement_set.addInsert(
target_path_or_descriptor._j_table_descriptor, table._j_table, overwrite)
return self
[docs] def explain(self, *extra_details: ExplainDetail) -> str:
"""
returns the AST and the execution plan of all statements and Tables.
:param extra_details: The extra explain details which the explain result should include,
e.g. estimated cost, changelog mode for streaming
:return: All statements and Tables for which the AST and execution plan will be returned.
.. versionadded:: 1.11.0
"""
j_extra_details = to_j_explain_detail_arr(extra_details)
return self._j_statement_set.explain(j_extra_details)
[docs] def execute(self) -> TableResult:
"""
execute all statements and Tables as a batch.
.. note::
The added statements and Tables will be cleared when executing this method.
:return: execution result.
.. versionadded:: 1.11.0
"""
self._t_env._before_execute()
return TableResult(self._j_statement_set.execute())