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PQL CLEAR()

The Clear() write call disassociates or unassigns a value from a record in a specified field.

For Set, Mutex, and Time fields, you can disassociate one value from one record at a time.

For Int, Decimal, and Timestamp fields, you can set the value for a given record to null by using any value for FIELD_VALUE – see example 2 below.

Call Definition 

Clear(UINT_OR_STRING, FIELD=FIELD_VALUE)

Mandatory Arguments

  • UINT_OR_STRING: the record we’d like to operate on – UNIT or unsigned integer for non-keyed indexes and string for keyed indexes.
  • FIELD : the name of the field that contains the value we want to disassociate with the record
  • FIELD_VALUE : the value we want to disassociate with the record - use the value of null for Int, Decimal, and Timestamp fields if you want to clear a value - i.e. set the value to null.

Optional Arguments

Returns

  • boolean
    • true indicates the write was successful
    • false indicates the write was unsuccessful or nothing changed

Examples

Example 1

Customer 5 as decided they don’t want the company to store their purchase data - remove it with Clear().

Data Pre-Query 

Index: customer (non keyed index)

 _id | age (Int) | has_purchased (Set) | last_purchase (Timestamp)
-----+-----------+---------------------+---------------------------
 0   |    23     | ["brand1","brand2"] | 2021-01-05T08:30:00Z
 1   |    31     | ["brand1","brand3"] | 2020-09-12T12:30:00Z
 2   |    28     | ["brand1","brand3"] | 2021-08-06T16:15:00Z
 3   |    19     | []                  | null
 4   |    25     | ["brand1","brand4"] | 2021-10-01T20:45:00Z
 5   |    40     | ["brand4"]          | 2022-01-13T11:00:00Z

Query 

[customer]Clear(5, has_purchased=brand4)

Tabular Response 

 result
--------
 true

Data Post-Query 

 _id | age |    has_purchased    |    last_purchase
-----+-----+---------------------+----------------------
 0   | 23  | ["brand1","brand2"] | 2021-01-05T08:30:00Z
 1   | 31  | ["brand1","brand3"] | 2020-09-12T12:30:00Z
 2   | 28  | ["brand1","brand3"] | 2021-08-06T16:15:00Z
 3   | 19  | []                  | null
 4   | 25  | ["brand1","brand4"] | 2021-10-01T20:45:00Z
 5   | 40  | []                  | 2022-01-13T11:00:00Z

Example 2

Customer 5 also doesn’t want the company to store their last_purchase data - remove it with Clear().

Data Pre-Query 

 _id | age |    has_purchased    |    last_purchase
-----+-----+---------------------+----------------------
 0   | 23  | ["brand1","brand2"] | 2021-01-05T08:30:00Z
 1   | 31  | ["brand1","brand3"] | 2020-09-12T12:30:00Z
 2   | 28  | ["brand1","brand3"] | 2021-08-06T16:15:00Z
 3   | 19  | []                  | null
 4   | 25  | ["brand1","brand4"] | 2021-10-01T20:45:00Z
 5   | 40  | []                  | 2022-01-13T11:00:00Z

Query 

[customer]Clear(5, last_purchase=null)

Tabular Response 

 result
--------
 true

Data Post-Query 

 _id | age |    has_purchased    |    last_purchase
-----+-----+---------------------+----------------------
 0   | 23  | ["brand1","brand2"] | 2021-01-05T08:30:00Z
 1   | 31  | ["brand1","brand3"] | 2020-09-12T12:30:00Z
 2   | 28  | ["brand1","brand3"] | 2021-08-06T16:15:00Z
 3   | 19  | []                  | null
 4   | 25  | ["brand1","brand4"] | 2021-10-01T20:45:00Z
 5   | 40  | []                  | null