Class PredefinedExpression (0.6.10)

    -  STRING: ""
    -  BYTES: b''
    -  INTEGER: 0
    -  FLOAT: 0.0
    -  NUMERIC: 0
    -  BOOLEAN: FALSE
    -  TIMESTAMP: 1970-01-01 00:00:00 UTC
    -  DATE: 1970-01-01
    -  TIME: 00:00:00
    -  DATETIME: 1970-01-01T00:00:00
    -  GEOGRAPHY: POINT(0 0)
    -  BIGNUMERIC: 0
    -  ARRAY: []
    -  STRUCT: NOT_APPLICABLE
    -  JSON: NULL
LAST_FOUR_CHARACTERS (9):
    Masking expression shows the last four characters of text.
    The masking behavior is as follows:

    -  If text length > 4 characters: Replace text with XXXXX,
       append last four characters of original text.
    -  If text length <= 4 characters: Apply SHA-256 hash.
FIRST_FOUR_CHARACTERS (10):
    Masking expression shows the first four characters of text.
    The masking behavior is as follows:

    -  If text length > 4 characters: Replace text with XXXXX,
       prepend first four characters of original text.
    -  If text length <= 4 characters: Apply SHA-256 hash.
EMAIL_MASK (12):
    Masking expression for email addresses. The masking behavior
    is as follows:

    -  Syntax-valid email address: Replace username with XXXXX.
       For example, cloudysanfrancisco@gmail.com becomes
       XXXXX@gmail.com.
    -  Syntax-invalid email address: Apply SHA-256 hash.

    For more information, see `Email
    mask <https://cloud.google.com/bigquery/docs/column-data-masking-intro#masking_options>`__.
DATE_YEAR_MASK (13):
    Masking expression to only show the year of `Date`,
    `DateTime` and `TimeStamp`. For example, with the year
    2076:

    -  DATE : 2076-01-01
    -  DATETIME : 2076-01-01T00:00:00
    -  TIMESTAMP : 2076-01-01 00:00:00 UTC

    Truncation occurs according to the UTC time zone. To change
    this, adjust the default time zone using the `time_zone`
    system variable. For more information, see the System
    variables reference.