A relational database is structure to recognize relations among information, and stores the information in tables. An object-oriented database focuses on presenting the information in the form of objects, to be used for object-oriented programming. Object-relational databases are a hybrid of the two, keeping relations stored but still keeping the object-type data. Relational databases are best for presentation of the data itself, while object-oriented databases are better for deriving new information from given information.
Data servers are good if data transfer is small with respect to computation, which is often the case in applications of OODBs such as computer aided design. In contrast, in typical relational database applications such as transaction processing, a transaction performs little computation butmay touch several pages, which will result in a lot of data transfer with little benefit in a data server architecture. Another reason is that structures such as indices are heavily used in relational databases, and will become spots of contention in a data server architecture, requiring frequent data transfer. There are no such points of frequent contention in typical current-day OODB applications such as computer aided design.
Relation algebra is a procedural language where relation calculus is non-procedural languageRelational algebra, an offshoot of first-orderlogic (and of algebra of sets), deals with a set of finitaryrelations (see also relation (database)) which is closed under certain operators. These operators operate on one or more relations to yield a relation. Relational algebra is a part of computer science.Relational calculus consists of two calculi, the tuplerelational calculus and the domain relational calculus, that are part of the relational model for databases and provide a declarative way to specify database queries. This in contrast to the relational algebra which is also part of the relational model but provides a more procedural way for specifying queries.The relational algebra might suggest these steps to retrieve the phone numbers and names of book stores that supply Some Sample Book:1. Join books and titles over the BookstoreID.2. Restrict the result of that join to tuplesfor the book Some Sample Book.3. Project the result of that restriction over StoreNameand StorePhone.The relational calculus would formulate a descriptive, declarative way:Get StoreNameand StorePhonefor supplies such that there exists a title BK with the same BookstoreIDvalue and with a BookTitlevalue of Some Sample Book.The relational algebra and the relational calculus are essentially logically equivalent: for any algebraic expression, there is an equivalent expression in the calculus, and vice versa.This result is known as Codd'stheorem
A flat-table database is one that uses a single table to store all relevant data. By contrast, a relational database uses several tables to store relevant data, and then establishes 'relations' between them using unique identifiers ... such as primary keys and foreign keys. Flat-table databases are ok if the data is not too complex or repetitive. Relational databases are good when the data is complex and repetative. For example: Keeping track of a personal music CD collection - if one is lazy - can simply be done in a flat-table database table (or a spread sheet). It can also be done in a relational database by creating a few tables and relating them. One table can be artist (with a primary key), another table can be album (relates to a single artist primary key), and a third can be a record label table (which can relate to many artist primary keys). This is a very high-level view of the differences. I .
data manipulation language, belongs to databases and sql. queries like insert/update/delete. in contrast, queries like create/alter/drop are called ddl (data definition language)
Normally it is "in contrast with..." But "to" is used when the difference is being emphasized.
There is no modern contrast or indeed any ancient contrast.
I will contrast these two plants.
The class has to write a compare and contrast essay. The contrast between the two items is striking. Their personalities are in contrast to each other.
its something when a mommy contrast generalist does bonding with the daddy contrast generalist and they then form a baby contrast generalist and so forth =D
The word 'contrast' is a noun (contrast, contrasts) and a verb (contrast, contrasts, contrasting, contrasted). Examples:noun: The contrast in their personalities makes them seem like a very odd couple.verb: We need to choose accessories to contrast with the outfit.
Contrast is the light thing that you need for your pictureContrast is created by the difference in luminance, the amount of reflected light, reflected from two adjacent surfaces.There is also the Weber definition of contrast: Contrast =Lmax - LminLmaxLmax = Luminance on the lighter surfaceLmin = Luminance on the darker surfaceWhen the darker surface is black and reflects no light, the ratio is 1. Contrast is usually expressed as percent; the ratio is multiplied by 100. The maximum contrast is thus 100% contrast. The symbols of the visual acuity charts are close to the maximum contrast. If the lowest contrast perceived is 5%, contrast sensitivity is 100/5=20. If the lowest contrast perceived by a person is 0.6%, contrast sensitivity is 100/0.6=170.Weber Contrast; C= (Lmax-Lmin)/Lmin.
contrast science and technology
What is the comparison and contrast of Paleolithic?
how do you compare and contrast hydrographs
A contrast medium
A contrast agent
Compare and contrast it with what?
When you can not contrast or compare.
use contrast in sentence.
Contrast is the difference between the "empties" and the "fulls".
Contrast the nucleus and nucleolus
what is the definition of comparison and contrast writing
contrast of us and philippines