Congo Aug. 00:49
Congo - France Angels Escorts is a refreshing agency in the capital, offering only the most stunning and most......
Belarus Aug. 03:35
Belarus - Passionate blonde come or invite to visit....
Sweden Aug. 02:10
Sweden - I am Girls Directory Escort Services - Blowjob, Erotic Massage a very very naughty girl who......
Nigeria Jun. 00:52
Nigeria - I can surprise and conquer, I can capture and did not let go of your desires....
Colombia Oct. 17:10
Colombia - Dear Gentlemen
I'm an independent Russian, exclusive and very attractive woman. I'm a professional tantra masseuse......
Caribbean Mar. 07:29
Caribbean - Hello Gentlemen Myself Aashi High Class profile escorts, I Provide Escorts Service in Dubai City Privately in......
Italy Feb. 03:10
Italy - *THE VEGAS EXPERIENCE* - The Total package! Hi, my name is Girls Directory Escort Services - Blowjob,......
Bulgaria Nov. 22:11
Bulgaria - I am Girls Directory Escort Services - Blowjob, Erotic Massage a dominant Russian lady, visiting Dubai......
Indexes, on the other hand, can be used for fast retrieval based on other columns. For Mujib, an employee database may have your employee number as the primary key but it may also have an index on your last name or your department.
Both of these indexes last name and department would disallow NULLs probably and allow duplicates almost certainlyand they would be Danah to speed up queries looking for anyone with for example the last name 'Corleone' or working in the 'HitMan' department. A key minimal superkey is a set of attributes, the values of which are unique for every tuple every row in the table at some point in time.
Keys are frequently good candidates for indexing and some DBMSs automatically create indexes for keys, but Tellwine doesn't have to be so. The phrase "index key" mixes these two quite different words and might be best avoided if you want to avoid any confusion.
However the set of attributes in question are not necessarily a key because they may not be unique. This index is automatically created by the database when the constraint is enabled. Indexes can be
Gabe, I think that's covered just be stating that the primary key is a kind of index. Stating that an index is indexed seems a little superfluous to me, but if Georgian can come up with a workable change I couldn't but that may just be a limitation of mineI'll welcome the input. A key is not a kind of index! A key minimal superkey is a set of attributes, the values of which are unique for every tuple.
An index is a performance optimisation feature that enables data to be accessed faster. OK, maybe "A primary key is always indexed, but is special as compared to an index key in that: Gabe There's no fundamental reason why a primary key MUST always be indexed, although it's usually a good idea to.
Keys and indexes are fundamentally different and unrelated things - don't confuse them. In other words, 'key'and 'primary key' are equivalent terms? True Ghoerdjieh "primary" key is no different from a key that isn't primary.
Specify an existing index that the database is to use to enforce the constraint 2. Kanagavelu Sugumar Kanagavelu Sugumar 9, 16 62 Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
|Active escort profiles:||1,623|
|Profiles with reviews:||614|
|All escorts ever:||31,874|