Chapter 03 The Relational Database Model
Referential integrity ensures that every row is uniquely identified by the first key. 39) When you outline a table’s primary key, the DBMS automatically creates a ______ index on the first key column you declared. 26) A ________ be part of hyperlinks tables by deciding on solely the rows with common values of their frequent attribute. 2) The relational database model lets you view data _____ rather than ____. A ____ be part of hyperlinks tables by selecting solely the rows with widespread values of their frequent attribute.
To be thought of minimally relational, the DBMS should support the vital thing relational operators ____, PROJECT, and JOIN. A ____ key could be described as a superkey without pointless attributes, that is, a minimal superkey. The _____ constraint can be positioned on a column to make sure that each row in the desk has a worth for that column. Only a single attribute, not multiple attributes, can outline practical dependence.
The relational database model lets you view information ____ somewhat than ____. When you define a table’s main key, the DBMS automatically creates a ____ index on the primary key column you declared. Question four of 35 1 Points The entity supertype contains frequent characteristics, and the entity subtypes every comprise their very own unique characteristics. Question 25 of 35 1 Points The entity relationship diagram represents the _____ database as considered by the top user. Question 25 of 35 1 Points A _____ join links tables by choosing solely the rows with frequent values of their frequent attribute.
The set of potential values for an attribute is a ___. The ERD represents the ___ database as viewed by the tip consumer. A ___ incorporates no less than all the attribute names and characteristics for every desk within the system. To be considered minimally relational, the DBMS must armor blitz relationship help the necessary thing relational operators ____, PROJECT and JOIN. The ___ constraint can be positioned on a column to make sure that each row within the desk has a worth for that column. A ___ key could be described as a superkey with out pointless attributes, that’s, a minimal superkey.
Overlapping subtypes are subtypes that comprise ___ subsets of the supertype entity set. Non-overlapping subtypes are subtypes that include a ___ subset of the supertype entity set. If the focus is on data-retrieval speed, you would possibly also be pressured to incorporate ___ attributes in the design, which would not ordinarily be carried out. Some ___ database modeling ideas may be expressed solely using the Chen notation.
_____ is a language based mostly on OO ideas that describes a set of diagrams and symbols used to graphically mannequin a system. The ___ model was developed to allow designers to make use of a graphical software to look at structures rather than describing them with textual content. The external mannequin is the illustration of the database as “seen” by the DBMS.
Data dictionary should embody desk name, attribute names, contents, type, format, domain, required, PK or FK, FK referenced table. 18) All major key entries are distinctive, and no part of a major key may be _____. 7) In the relational mannequin, _____ are essential because they’re used to ensure that each row in a desk is uniquely identifiable. In the relational model, ____ are essential because they’re used to ensure that every row in a table is uniquely identifiable. A verb associating two nouns in a business rule interprets to a ____ in the knowledge model. A noun in a enterprise rule interprets to a ____ in the data model.
Knowing the ___ number of entity occurrences could be very useful at the application software level. A derived attribute is indicated in the Chen mannequin by a ____. A ___ attribute can be further subdivided to yield further attributes. The attribute B is ___ the attribute A if each worth in column A determines one and only one worth in column B. The ___ model uses the time period connectivity to label the relationship sorts.
___ keys work with main keys to properly implement relationships in the relational model. The CUSTOMER main key column has no null entries, and all entries are unique. Question 22 of 35 1 Points The CUSTOMER table’s major secret is CUS_CODE. _____ keys work with primary keys to correctly implement relationships in the relational mannequin. A ______ offers a detailed description of all tables found within the user/designer-created database. In a relational mannequin, _____ are used to ascertain relationships among tables and to ensure the integrity of the data.