update_records

GPUdb.update_records( table_name = None, expressions = None, new_values_maps =
                      None, records_to_insert = [], records_to_insert_str =
                      [], record_encoding = 'binary', options = {} )

Runs multiple predicate-based updates in a single call. With the list of given expressions, any matching record's column values will be updated as provided in input parameter new_values_maps. There is also an optional 'upsert' capability where if a particular predicate doesn't match any existing record, then a new record can be inserted.

Note that this operation can only be run on an original table and not on a collection or a result view.

This operation can update primary key values. By default only 'pure primary key' predicates are allowed when updating primary key values. If the primary key for a table is the column 'attr1', then the operation will only accept predicates of the form: "attr1 == 'foo'" if the attr1 column is being updated. For a composite primary key (e.g. columns 'attr1' and 'attr2') then this operation will only accept predicates of the form: "(attr1 == 'foo') and (attr2 == 'bar')". Meaning, all primary key columns must appear in an equality predicate in the expressions. Furthermore each 'pure primary key' predicate must be unique within a given request. These restrictions can be removed by utilizing some available options through input parameter options.

Input Parameter Description

Name	Type	Description
table_name	str	Table to be updated. Must be a currently existing table and not a collection or view.
expressions	list of str	A list of the actual predicates, one for each update; format should follow the guidelines here.
new_values_maps	list of dicts of str, and None	List of new values for the matching records. Each element is a map with (key, value) pairs where the keys are the names of the columns whose values are to be updated; the values are the new values. The number of elements in the list should match the length of input parameter expressions.
records_to_insert	list of str	An optional list of new binary-avro encoded records to insert, one for each update. If one of input parameter expressions does not yield a matching record to be updated, then the corresponding element from this list will be added to the table. Default value is an empty list ( [] ).
records_to_insert_str	list of str	An optional list of new json-avro encoded objects to insert, one for each update, to be added to the set if the particular update did not affect any objects. Default value is an empty list ( [] ).
record_encoding	str	Identifies which of input parameter records_to_insert and input parameter records_to_insert_str should be used. Default value is 'binary'. The allowed values are: binary json
options	dict of str	Optional parameters. Default value is an empty dict ( {} ). Supported Parameters (keys) Parameter Description global_expression An optional global expression to reduce the search space of the predicates listed in input parameter expressions. Default value is ''. bypass_safety_checks When set to 'true', all predicates are available for primary key updates. Keep in mind that it is possible to destroy data in this case, since a single predicate may match multiple objects (potentially all of records of a table), and then updating all of those records to have the same primary key will, due to the primary key uniqueness constraints, effectively delete all but one of those updated records. Default value is 'false'. The allowed values are: True False update_on_existing_pk Can be used to customize behavior when the updated primary key value already exists, as described in insert_records. Default value is 'false'. The allowed values are: True False record_id ID of a single record to be updated (returned in the call to insert_records or get_records_from_collection).

Output Parameter Description

Name	Type	Description
count_updated	long	Total number of records updated.
counts_updated	list of longs	Total number of records updated per predicate in input parameter expressions.
count_inserted	long	Total number of records inserted (due to expressions not matching any existing records).
counts_inserted	list of longs	Total number of records inserted per predicate in input parameter expressions (will be either 0 or 1 for each expression).