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What is a composite or bridge entity in database terms and when is it used?
Wiki User
∙ 10y ago
it is an entity whose primary key is composed of the combination of the primary keys of the entities that must be linked. It is used in linking tables of the M:N relationship that needs to be converted into two 1:M relationship for your database
Wiki User
∙ 10y ago
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What is significance of diagonal terms of variance-covariance matrix?
The diagonal terms give the variances. The square root of which gives the standard deviations. The diagonal terms give the variances. The square root of which gives the standard deviations.
What are advantages of slump test?
The slump test is the most widely used device worldwide. In fact, the test is so well known that often the terms workability and slump are used interchangeably, even though they have different meanings. • Specifications are typically written in terms of slump. • The slump test is simple, rugged, and inexpensive to perform. Results are obtained immediately. • The results of the slump test can be converted to yield stress in fundamental units based on various analytical treatments and experimental studies of the slump test. • Compared to other commonly used concrete tests, such as for air content and compressive strength, the slump test provides acceptable precision.
What is workability?
Workability refers to the ease of which the soil can be physically controlled for the purpose of cultivation. For example, if tilling or digging the soil produces cloddy or plate like clumps, the workability is low. From what I already know, clay soils aren't the best in terms of workability because it clumps together and is difficult to break up, whilst sandy soils usually have a much better workability but tend to be poor for cultivation because of other reasons.
What is a variation of contract?
Variations are a common feature of building projects. The client or client's agent has the right to alter the designs or specifications to the build and the contractor is entitled to charge for these alterations if he is instructed to carry out these variations/extras. Be aware, that there will be additional costs incurred if scaffolding for example has to be altered or hired for longer durations, as a result of these changes. The contractor is also entitled to an extension of time on to the original time frame and the adjustment to the next stage payments to reflect these variations will be affected. It is best practice for the contractor to flag these issues and to explain to the client or agent how these variations will affect the original contract price and time scale once the variations have been suggested so that everyone is kept in the loop. Note that a variation can also mean that the cost may be reduced to reflect this, if an item is omitted or specification is reduced from the original.
What is the difference between box culvert and pipe?
Basically, a culvert means a covered hydraulic structure which conveys fluid. Therefore in a broad sense, pipe culverts in a small scale represent normal pipes like precast concrete pipes. In terms of hydraulic performance, circular section is the best geometrical sections among all. Therefore, for relative small discharge, precast concrete pipes and ductile iron pipes are normally used which are circular in shape. But for applications of very large flow, precast concrete pipes and ductile iron pipes may not be available in current market. In this connection, cast-in-situ construction has to be employed. It is beyond doubt that the fabrication of formwork for circular shape is difficult when compared with normal box culvert structures. However, circular shape is the most hydraulic efficient structure which means for a given discharge, the area of flow is minimum. Therefore, it helps to save the cost of extra linings required for the choice of box culverts. However, box culverts do possess some advantages. For example, they can cope with large flow situation where headroom is limited because the height of box culverts can be reduced while the size of pipe culverts is fixed. Secondly, for some difficult site conditions, e.g. excavation of structure in rock, for the same equivalent cross-sectional area, the width of box culverts can be designed to be smaller than that of pipe culverts and this enhances smaller amount of excavation and backfilling
How can you determine whether an object is an entity or an attribute?
Information contributed by Ramona Maxwell:An entity is a primary object in your database design and an attribute would further describe that object. In human terms if you are the entity, your attributes might be height, age, hair color and so on. In a sales database 'customer' might be an entity whose attributes could include name, address or account number. Entities and or their attributes are mapped in terms of their relationship to one another when designing your database. Helpful information on Entity Relationship Modeling can be found at the following link:http:/enzperiodzwikipediazperiodzorg/wiki/Entityzhyphenzrelationship_model
Is the schema describes record relationship?
A database schema describes the overall logical structure and relationship of data within the database. Such a schema will include all joins within the database and describe the relational sets. It is best thought of as a written description in formal terms describing the entities/tables, their attributes and the relations between individual tables in terms of primary (local) keys, foreign keys. A primary key is the attribute (or set of attributes) whose value(s) is unique within an individual entity/table to access all data in a single record. A foreign key, is a key from another table/entity that is used to join an entity/table with another entity/table, so that all data records related to the primary key can be displayed.
What is an attribute and how many types?
An attribute in the database terms is called as fields. A group of fields is known as a record or tuple. Attributes can be either simple or composite and single or multi-valued .
What does composite in mathematical terms?
A composite number has more than two factors.
What does sort mean in database terms?
Khansahs head
Could an entity be a noun?
The names and terms for all entities are nouns.
What do you think a database is?
A database in computer terms is a system that organizes data. A database can have information about anything, ranging from music to different locations to travel.
What sequence represents the hierarchy of terms from smallest to largest from field record database and table?
field, record, table, database
What powerful entity controls the House schedule and the terms for debate?
Rules committee
What is financial stewardship?
Financial stewardship is when one entity assumes the financial responsibilities for another entity. The steward would be expected to act in the best intentions for the entity in terms of financial planning, investments and accountability.
What is the feature of fixed movable bridge?
You can't have a "fixed" "movable" bridge, the two terms are contradictory.
Difference between an entity class and an entity instance?
"An entity is a person, place, event, or thing about which data is collected...An instance is an occurence of an entity." - Systems Analysis & Design (4th) - DennisAn example of this would be STUDENT as the entity while JACK SMITH is an instance of that entity.If an entity is an individual "person, place, event, or thing about which data is collected", then an entity is an instance. Linguistically, entity is just another word for a single thing ("The existence of a thing as contrasted with its attributes.", Merriam-Webster's On-line Dictionary). Entities that have the same attributes are grouped in what are best called entity classes (it doesn't make sense to refer to a collection of entities as an entity). Entity and entity class are data modeling terms. The corresponding object modeling terms are object and class, albeit that a class typically has operations, which are foreign to an entity class.
