A specification of a relational table. The table's schema
is represented via its child column specs. It is pre-populated as part
of ImportData by schema inference algorithm, the version of which is a
required parameter of ImportData InputConfig. Note: While working with a
table, at times the schema may be inconsistent with the data in the
table (e.g. string in a FLOAT64 column). The consistency validation is
done upon creation of a model. Used by: * Tables
column_spec_id of the time column. Only used if the parent
dataset's ml_use_column_spec_id is not set. Used to split
rows into TRAIN, VALIDATE and TEST sets such that oldest rows
go to TRAIN set, newest to TEST, and those in between to
VALIDATE. Required type: TIMESTAMP. If both this column and
ml_use_column are not set, then ML use of all rows will be
assigned by AutoML. NOTE: Updates of this field will instantly
affect any other users concurrently working with the dataset.
Output only. The number of valid rows (i.e. without values
that don't match DataType-s of their columns).
Output only. Input configs via which data currently residing
in the table had been imported.