src/ports/postgres/modules/graph/graph_utils.py_in

# coding=utf-8
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# to you under the Apache License, Version 2.0 (the
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#   http://www.apache.org/licenses/LICENSE-2.0
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# under the License.

# Graph Methods

# Please refer to the graph.sql_in file for the documentation

"""
@file graph.py_in

@namespace graph
"""

import plpy
from utilities.control import MinWarning
from utilities.utilities import _assert
from utilities.utilities import extract_keyvalue_params
from utilities.utilities import unique_string
from utilities.validate_args import get_cols
from utilities.validate_args import unquote_ident
from utilities.validate_args import table_exists
from utilities.validate_args import columns_exist_in_table
from utilities.validate_args import table_is_empty


def validate_graph_coding(vertex_table, vertex_id, edge_table, edge_params,
	out_table, func_name, **kwargs):
	"""
	Validates graph tables (vertex and edge) as well as the output table.
	"""
	_assert(out_table and out_table.strip().lower() not in ('null', ''),
		"Graph {func_name}: Invalid output table name!".format(**locals()))
	_assert(not table_exists(out_table),
		"Graph {func_name}: Output table already exists!".format(**locals()))

	_assert(vertex_table and vertex_table.strip().lower() not in ('null', ''),
		"Graph {func_name}: Invalid vertex table name!".format(**locals()))
	_assert(table_exists(vertex_table),
		"Graph {func_name}: Vertex table ({vertex_table}) is missing!".format(
			**locals()))
	_assert(not table_is_empty(vertex_table),
		"Graph {func_name}: Vertex table ({vertex_table}) is empty!".format(
			**locals()))

	_assert(edge_table and edge_table.strip().lower() not in ('null', ''),
		"Graph {func_name}: Invalid edge table name!".format(**locals()))
	_assert(table_exists(edge_table),
		"Graph {func_name}: Edge table ({edge_table}) is missing!".format(
			**locals()))
	_assert(not table_is_empty(edge_table),
		"Graph {func_name}: Edge table ({edge_table}) is empty!".format(
			**locals()))

	existing_cols = set(unquote_ident(i) for i in get_cols(vertex_table))
	_assert(vertex_id in existing_cols,
		"""Graph {func_name}: The vertex column {vertex_id} is not present in vertex table ({vertex_table}) """.
		format(**locals()))
	_assert(columns_exist_in_table(edge_table, edge_params.values()),
		"""Graph {func_name}: Not all columns from {cols} are present in edge table ({edge_table})""".
		format(cols=edge_params.values(), **locals()))

	return None

def get_graph_usage(schema_madlib, func_name, other_text):

	usage = """
----------------------------------------------------------------------------
                            USAGE
----------------------------------------------------------------------------
 SELECT {schema_madlib}.{func_name}(
    vertex_table  TEXT, -- Name of the table that contains the vertex data.
    vertex_id     TEXT, -- Name of the column containing the vertex ids.
    edge_table    TEXT, -- Name of the table that contains the edge data.
    edge_args     TEXT{comma} -- A comma-delimited string containing multiple
                        -- named arguments of the form "name=value".
    {other_text}
);

The following parameters are supported for edge table arguments ('edge_args'
	above):

src (default = 'src')		: Name of the column containing the source
				vertex ids in the edge table.
dest (default = 'dest')		: Name of the column containing the destination
				vertex ids in the edge table.
weight (default = 'weight')	: Name of the column containing the weight of
				edges in the edge table.
""".format(schema_madlib=schema_madlib, func_name=func_name,
	other_text=other_text, comma = ',' if other_text is not None else ' ')

	return usage