Assingment2 Essay

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ITC 6000 Class 2 ‐ Assignment
1. List at least four advantages of indexing. Mention some indexing tips that would be of particular help to a database designer. Also, discuss indexing practices that can adversely affect the performance of a database. In your discussion, include information on how a designer should decide on how many indexes to provide per table.
Indexes are used to boost performance in a database. Finding an individual record or set of records most efficiently done by Index. Index key is the reference point where an index is an ordered arrangement of keys and pointers. Each key is appointed to the location of the data recognized by the key. For example: when we print out at the NEU library we have given our User ID so
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Not updated: Look for information that is not subject to change when identifying primary keys. ID numbers instead for Names.
Required: If the key is defined within a table, it will never have a null value. Information cant referenced without a Primary key. Value is required by the software.
Combination Keys: A primary key can be made from a single field or combination of several fields. It could be made from a combination of student ID number and the time computer use started in a database. For an example: Computer user logs.
Identifying foreign keys: Every dependent and category entity in the design must have a foreign key for each relationship in which it participates. Foreign keys are formed in dependent and sub type entities by migrating the entire primary key from the parent or generic entity. If the primary key is composite, it may not be split.
Foreign key attributes are not considered to be owned by the entities that they migrate, because they are reflections of attributes in the parent entity. Each attribute in an entity is either owned by that entity or belongs to a foreign key in that entity.

3. Describe at least two examples of common errors in entity relationship modeling. If possible, provide a graphical illustration of the problems and solutions. List some questions the designer should consider before designing the models so that these errors can be avoided.
Incomplete data model type.

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