CH13(answers) - Exam (CH 13)...

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Unformatted text preview: Exam (CH 13) Name___________________________________ TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 1) Conventional files can be designed and built quite rapidly (compared to a database), and the concerns for data availability and security are minimized by using them. 1) 2) The sharing of the data means that data need to be stored only once. 2) 3) Data have a better chance of being available in a conventional file system than in a database. 3) 4) Many users extract parts of the central database and download them onto personal computers. 4) 5) Within the realm of metadata, there are record definitions and data item definitions. 5) 6) Any object or event about which someone chooses to collect data is an attribute. 6) 7) An entity subtype is an entity that is used to represent a many- to- many relationship. 7) 8) An associative entity is used for repeating groups. 8) 9) Many data items can be packed into a field; the field can be read and converted to a number of data items. 9) 10) A primary key is one of the data items in a record that uniquely identifies a record. 10) 11) An object identifier is a unique key for each record in the database, not just in a table. 11) 12) Secondary keys can be used to select a group of records that belong to a set. 12) 13) Metadata describes the name given and the length assigned each record. 13) 14) Master files are large and contain all the information about an entity. 14) 15) Table files are used to update master files. 15) 16) Transaction files contain information necessary to produce reports but are not able to update master files. 16) 17) One of the primary advantages of the relational structure is that ad hoc queries are efficiently handled. 17) 18) A one- to- many relationship may be implemented using a drop- down list. 18) 19) A many- to- many relationship may be implemented using three tables. 19) 1 20) Each distinct data entity may be stored on several master database tables. 20) 21) A specific non- key data field should exist on only one master database table. 21) 22) Referential integrity means that all foreign keys in the many table must have a matching record in the parent table. 22) 23) A deletion anomaly occurs when the entire primary key is not known and the database cannot delete a record. 23) 24) An update anomaly occurs when the same data are stored in more than one place in the database. 24) 25) An outer join contains all the records from one table and matching records from the other table. 25) 26) Projection creates a new relation by extracting records that contain an attribute meeting a certain condition. 26) 27) Indexing is the logical ordering of rows in a relation according to some key. 27) 28) Presentation of the data abstracted from the database must take one of two forms: graphs and tabular forms....
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This note was uploaded on 01/11/2012 for the course ACCOUNTING ACOM taught by Professor Sanchocastro during the Spring '11 term at De La Salle University.

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CH13(answers) - Exam (CH 13)...

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