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Databases Demystified
Demystified / Databases Demystified / Oppel/ 225 364 -9 / Chapter 7
The Data Flow Diagram
The data flow diagram (DFD) is the most data centric of all the ... privileges.
6. The update anomaly refers to a situation where:
a. A simple update requires updates to multiple rows of data.
b. Data cannot be updated because it do...
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... models, a brief his
-
tory of databases, and the rationale for focusing on the relational model.
Properties of a Database
A database is a collection of interrelated data items that are managed as a ... database can be defined as the file
that contains the data items. Oracle Corporation defines their database as a collec
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tion of physical files that are managed by an instance of...
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... screen
Constraints
A constraint is a rule placed on a database object (typically a table or column) that
restricts the allowable data values for that database object in some way. These are
most important ... relational databases were built by both IBM and UC Berkeley.
e. Nearly all the commercial relational databases are descendents of either
System R or INGRES.
18. Currently avai...
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... row are called aggregate functions. The following table shows
aggregate functions that are commonly used in relational databases:
Function Name Description
AVG Calculates the average value for a ... one-to-many, one-to-one, or many-to-many
5. The Microsoft Access Show Table dialog box:
a. Lists all tables in the database and allows for the metadata about tables
to be added, changed, and...
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... that ends every SQL statement.
In Oracle, a transaction is automatically started for each database user session as soon
as the user connects to the database. At any time, the database user can ... table’s data.
The ALTER TABLE Statement
The ALTER TABLE statement may be used to change many aspects of the definition
of a database table. Again, there is a wide variation in implementation a...
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... normalization rules
•
Storing redundant data in tables
•
Storing summarized data in tables
Note also that normalization is intended to remove anomalies from databases that
are used for online transaction-processing ... identify any additional indexes that
may be necessary to achieve acceptable database performance. An essential out
-
come of this phase is the DDL for creation of the develop...
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... several proprietary XML databases
on the market. However, businesses have been reluctant to abandon relational data
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bases and undergo a major paradigm shift in the way they organize and store data.
So, ... considered
a best practice because it can lead to a lack of data sharing. Moreover, placing
geographic or organizational unit names in table names plays havoc every
time the organ...
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... even to a different version of the same vendor’s database).
Connecting Databases to Java Applications
Java started as a proprietary programming language (originally named Oak) that was
developed ... that
binds the API to the particular database and platform, and a definition known as the
ODBC data source contains the information necessary for a particular application to
connect with...
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... contains more data than a data warehouse.
e. The project has a lower overall cost than a data warehouse project.
16. Building a data warehouse first, followed by data marts:
a. Will delay data mart ... screen
CHAPTER 12 Databases for Online Analytical Processing
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Demystified / Databases Demystified / Oppel/ 225 364 -9 / Chapter 12
Data Marts
A data mart is a subset of...
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... entire, 62 63
D
Data Control Language (DCL), 90, 122–124
Data Definition Language (DDL), 90, 118–122
data encryption, 2 56 257
data flow diagram, 194–1 96
data integrity, 214
Data Manipulation Language ... their own tags
65 . A URL may contain
a. A host name or IP address
b. An SQL statement
c. A port
d. A web page
e. The absolute path to a resource on a web server
66 . An i...