Lesson 9: Using Databases

How can a client-server application architecture be described if it could be re-developed to split the application and presentation layers? A. This could be described as a two-tier application capable of becoming a tier-three application. B. This could be described as a one-tier application capable of becoming a tier-two application. C. This could be described as a three-tier application capable of becoming a n-tier application. D. This could be described as a n-tier application that cannot be further re-developed.

A. This could be described as a two-tier application capable of becoming a tier-three application. This is a two-tier application that can be redesigned into a three-tier application by specifying presentation, application, and data layers. Client-server applications can progress over time from one-tier up to n-tier structures through re-development. With each increased tier, the client/server application becomes more complex. A one-tier application can be re-developed into a two-tier application by separating the database engine from the business logic. A three-tier application already has the application and presentation layers split. Further re-development into an n-tier application architecture is possible by implementing an even more complex architecture, like using separate access controls. A two-tier application can be re-developed to split the application and presentation layers, resulting in a three-tier application. The term n-tier can apply to both two-tier and three-tier applications; however, the scenario describes the potential for further re-development.

You need a development environment with a library of database functions. What type of interface are you using? A. Direct/Manual Access B. Programmatic access C. Query/Report Builder D. Utility Access

B. Programmatic access Programmatic access is where a software application can interact with the database either using SQL commands or using SQL commands stored as procedures in the database. Most programming languages include libraries to provide default code for connecting to a database and executing queries. Manual access is where administrators might use an administrative tool such as phpMyAdmin to connect and sign in to an RDBMS database. Once they have connected, they can run SQL commands to create new databases on the system and interact with stored data. Query is done when there are many users who may need to interact closely with the database but do not want to learn SQL syntax. A query or report builder provides a GUI for users to select actions to perform on the database and converts those selections to the SQL statements that will be executed. Utility Access happens when an application might use a database "in the background" without the user really being aware of its presence. Alternatively, the application might provide a specific Graphical User Interface (GUI) or form to allow ordinary users to add and search records.

What term is used to describe selecting and viewing information in a database? A. Report B. Query C. Storage D. Create

B. Query A query allows the user to specify criteria to match values in one or more fields and choose which fields to display in the results so that only information of interest is selected. A report is a means of formatting and summarizing the records returned by a query so that the information is easy to read and interpret. A database represents a way for an application to store data persistently and securely. A query is used to retrieve information that is stored in a database. A database must first be created before it can store information and be queried. The creation step involves defining what information the database will store, where it will be hosted, and how it will be accessed by clients.

Give two examples of semi-structured data stores. A. Relational databases and text files B. Key/value pair database and PowerPoint presentations C. Key/value pair databases and markup language document stores. D. Word documents and PowerPoint presentations

C. Key/value pair databases and markup language document stores. Semi-structured data lacks the structure of a formal database architecture but adds associated metadata to raw unstructured data. This helps identify the data. Two examples of semi-structured data are key/value pair databases and markup language documentation stores. A key/value pair database is semi-structure; however, PowerPoint presentations are considered unstructured data. A relational database is considered structured data and a text file is considered unstructured data. Both Word documents and PowerPoint presentations are considered unstructured data. Semi-structured data uses metadata to help identify the contents of the data.

What are the structural elements of a database? A. Each table stores information about queries and reports. B. Each query stores information about tables in reports. C. Each report stores information about tables in fields. D. Each table stores information about records in fields.

D. Each table stores information about records in fields. A database is an organized collection of information that consist of tables of information, organized into columns and rows. Each row represents a separate record while each column represents a single field within a record. A query is a process that extracts information from a database's tables based on criteria. A query might return a large number of records that, once formatted, becomes a report. A report consists of formatted information that is returned by a query and is not considered a structural element. A table is a structural element that consists of records (or rows) of fields (or columns). Queries and reports are processes or tools associated with databases.

How does Microsoft SQL Server differ from Microsoft Excel when used to store a dataset? A. Excel is an example of relational database software that is better suited for larger volumes of information and more users, whereas SQL Server is a flat file system. B. Excel is an example of relational database software, whereas SQL Server is a flat file system that is better suited for larger volumes of information and more users. C. Excel is an example of a flat file system that is better suited for larger volumes of information and more users, whereas SQL Server is relational database software. D. Excel is an example of a flat file system, whereas SQL Server is relational database software that is better suited for larger volumes of information and more users.

D. Excel is an example of a flat file system, whereas SQL Server is relational database software that is better suited for larger volumes of information and more users. Microsoft Excel is an example of a flat file system. These do not scale well, and usually support a single user only. Relational Database Management System (RDBMS) platforms enable many hundreds or thousands of users to connect concurrently, and can support very large datasets. Also, an RDBMS can enforce data types for each column and validate information entered as fields and records. SQL Server is an example of a RDBMS, and Excel is an example of a flat file system. Excel is a flat file system, not an RDBMS. SQL Server is the RDBMS that is better suited for larger volumes of information and more users. Flat file systems are not suited for larger volumes of information and more users. Flat file systems are better with smaller datasets and singles users.

Which of the following is NOT an example of unstructured data? A. PowerPoint presentation B. Image files C. Text files D. Relational databases

D. Relational databases Unstructured data provides no rigid formatting of the data. Unstructured data is typically much easier to create than structured data. There are many examples of unstructured data; however, relational database is not unstructured. A relational database is considered structured data. Structured data enables easier access to the stored information and increased flexibility over retrieving exactly what you are looking for. Image files do not provide rigid formatting and are therefore considered unstructured data. Text files do not provide rigid formatting and are therefore considered unstructured data. PowerPoint presentations do not provide rigid formatting and are therefore considered unstructured data.

How is a relationship identified between two tables in an RDBMS? A. Each table contains a foreign key whose value is unique for each record in the table. A foreign table can use the value of a foreign key as a relation, storing the value in a primary key field. B. Each table contains a primary key whose value is unique for each record in the table. A foreign table can use the value of a primary key as a relation, storing the value in a foreign key field. C. A relationship between tables is created and identified by the schema. D. A constraint defines the relationship between tables.

B. Each table contains a primary key whose value is unique for each record in the table. A foreign table can use the value of a primary key as a relation, storing the value in a foreign key field. In an RDBMS, the primary and foreign keys define the relationship between tables. Each table contains a primary key whose value is unique for each record in the table. A foreign table can use the value of a primary key as a relation, storing the value in a foreign key field. Each table has a primary key that is unique to each record in the table. In a foreign table, the primary key of the original table is stored as a foreign key. A schema is used to define the overall structure of a database and the objects that exist. A relationship between tables is created and identified by the use of primary and foreign keys. A constraint is something imposed on values that can be input into each field of a table. A constraint does not define the relationship between tables.

What language is usually used to request data from an RDBMS such as Oracle? A. eXtensible Markup Language (XML) is used to query RDMBS-based database platforms. B. Structured Query Language (SQL) is used to query RDBMS-based database platforms. C. Hypertext Markup Language (HTML) is used to query RDBMS-based database platforms. D. Java is used to query RDBMS-based database platforms.

B. Structured Query Language (SQL) is used to query RDBMS-based database platforms. The Structured Query Language (SQL) is designed to retrieve specific records from a dataset. This is accomplished using the Data Definition Language (DDL) commands which are SQL commands that add to or modify the structure of a database. eXtensible Markup Language (XML) was designed to store and transport data. XML was also designed to be both human- and machine-readable. Hypertext Markup Language (HTML) is a language used to serve HTML web pages using coded tags to describe how the page should be formatted. Java is a general-purpose computer-programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few implementation dependencies as possible. General purpose programming languages can access database information using SQL queries.

An INSERT statement is an example of what data language type? A. Both Data Manipulation Language and Data Definition Language B. Data Definition language C. Data Manipulation Language D. Neither Data Manipulation Language nor Data Definition Language

C. Data Manipulation Language Data Manipulation Language (DML) commands allow you to insert or update records and extract information from records for viewing. Data Definition Language (DDL) commands refer to SQL commands that add to or modify the structure of the database. Therefore, the INSERT statement is part of DML because it depends on the structure of a table (columns, data types, and constraints) being established already. Data Definition Language (DDL) commands add to or modify the structure of a database. The INSERT statement manipulates an existing structure. A statement must be either a Manipulation or a Definition statement, not both. The INSERT statement fits the definition of a Data Manipulation Language because it inserts records into a pre-existing structure.