If you feel paranoid, schedule a regular VACUUM on the table in question, and make sure that you have no long running transactions. If I were called to court as an expert witness, I would say that anybody who has run DELETE in the database has taken all possible steps to erase the data. If the ELSE clause is omitted and no condition is true, the result is null. Once VACUUM has run, it is nigh impossible to do that. For example, 7 NULL yields null, as does 7 <> NULL.And it would take a data forensics expert with advanced PostgreSQL knowledge to retrieve such data. Ordinary comparison operators yield null (signifying unknown ), not true or false, when either input is null. My bet is that few enough people understand the inner workings of PostgreSQL well enough to contest that DELETE is erasure. The term “erasure” is nowhere defined in that law, so it is subject to interpretation. Its optional to populate data in such columns. The PostgreSQL table can be created with a column defined as nullable. NULL NULL results in NULL, as opposed to, which evaluates to TRUE. In PostgreSQL, a NULL means missing data. Finding the size or length of NULL results in NULL. The data subject shall have the right to obtain from the controller the erasure of personal data concerning him or her without undue delay and the controller shall have the obligation to erase personal data without undue delay It doesn’t have a value, as opposed to an empty string, which is a value but an empty one. All the remaining arguments from the first non-null argument are not evaluated. The COALESCE function evaluates arguments from left to right until it finds the first non-null argument. This PostgreSQL IS NULL example will insert records into the contacts table where the employeenumber contains a NULL value. VACUUM will not overwrite the data, so the old value will still be on disk until the space is reused. If all arguments are null, the COALESCE function will return null. The NULLIF function is one of the most common conditional expressions provided by PostgreSQL.VACUUM will only delete the old row version if there is no long running transaction that still might need old data.If you set columns to NULL, a new row version will be created just as with any other UPDATE, and the previous row versions will remain until VACUUM reclaims them. PostgreSQL never performs an UPDATE by modifying the existing data in place.
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