Answer:
Explanation:
Duplicate tuples are not allowed in a relation because the specifications of the constraints of the regional integrity are violated, especially the main constraint that states that there can be no identical values for the attributes of two tuples at any database relation state.
Also, duplicate tuples are not allowed in a relation due to the fact that they lead to redundancy of the data base which in turn, slowing down the speed of the database when data processing such as inserting, querying, updating, deleting, etc are being performed.
Answer:
The British inventor Fox Talbot produced his first successful photographic images in 1834, without a camera, by placing objects onto paper brushed with light-sensitive silver chloride, which he then exposed to sunlight.
Explanation:
Power both wind mills and water wheels produced power which was used for textile factories ect
<span>Spreading Activation
This is a model of working memory, which can be otherwise called here and now memory in lay man's term, that tries to clarify how the mind forms related thoughts, particularly semantic or verbal ideas. The spreading enactment show is one way intellectual clinicians clarify the preparing impact, which is the noticeable wonder that a man can all the more rapidly review data about a subject once a related idea has been presented. As indicated by this model, semantic long haul memory comprises of a huge, interrelated system of ideas. At the point when a man is given any idea, the ideas most firmly associated with it are initiated in that individual's psyche, getting ready or "preparing" him or her to review data identified with any of them</span>
Answer:
b
Explanation:
A computing grid can be thought of as a distributed system with non-interactive workloads that involve many files.
