Что (кто) такое null observation - определение
WIKIMEDIA DISAMBIGUATION PAGE
NULL; Null (computer programming); Null value; Null (computing); Null (Computing); Null (computer); Null (disambiguation); User:SideTime; (null); Nil (programming languages); Null (EP); Null values
Null allele
NONFUNCTIONAL ALLELE (A VARIANT OF A GENE) CAUSED BY A GENETIC MUTATION
Null mutation; Null Allele; Null alleles; Null mutant
A null allele is a nonfunctional allele (a variant of a gene) caused by a genetic mutation. Such mutations can cause a complete lack of production of the associated gene product or a product that does not function properly; in either case, the allele may be considered nonfunctional.
Null (SQL)
![omega (ω)]] character is used to represent Null in [[database theory]].](https://commons.wikimedia.org/wiki/Special:FilePath/Db null.png?width=200 "omega (ω)]] character is used to represent Null in [[database theory]].")
![outer join]] query with Null placeholders in the result set. The Null markers are represented by the word <code>NULL</code> in place of data in the results. Results are from [[Microsoft SQL Server]], as shown in SQL Server Management Studio.](https://commons.wikimedia.org/wiki/Special:FilePath/Sql query1.png?width=200 "outer join]] query with Null placeholders in the result set. The Null markers are represented by the word <code>NULL</code> in place of data in the results. Results are from [[Microsoft SQL Server]], as shown in SQL Server Management Studio.")
SPECIAL MARKER AND KEYWORD IN SQL INDICATING THAT SOMETHING HAS NO VALUE
Sql null; NULL (SQL); NVL; NULLIF; SQL CASE; Sql case; Codd tables; Codd table; COALESCE; C-table; Uncertain database; NULL marks; Null (database)
In SQL, null or NULL is a special marker used to indicate that a data value does not exist in the database. Introduced by the creator of the relational database model, E.
/dev/null
SPECIAL COMPUTER FILE THAT DISCARDS ALL WRITES
Dev/null; /dev/null/; NUL:; The null device; NUL (computer); NUL (Computer); Dev-null; \Device\Null; /dev/null; Unix null device; \DEV\NUL; /DEV/NUL; NIL:; $null; DD DUMMY; VMS NL:; NUL (device)
/dev-nuhl/ [The Unix null device, used as a data sink ] A
notional "black hole" in any information space being
discussed, used, or referred to. A controversial posting, for
example, might end "Kudos to rasputin@kremlin.org, flames to
/dev/null". See bit bucket.
[Jargon File ]
