Comp Sci Paper 2: Databases
A.4.10 Classification
The process of placing a particular data in a predefined group Bank manager finds a customer who will not pay loans in time.
A.4.10 Forecasting
The process of predicting possible problems that may arise using data available with the company if company grows in present state, it will not be able to meet increase price in near future
A.1.7 Consistency
The property of database that ensures that the database remains in consistent state before and after the transactions.
A.1.7 Isolation
The requirement that other operations cannot access or see the data in an intermediate state during a transaction.
A.1.7 Explain the importance of ACID properties of a database transaction
The set of properties that guarantee that database operations are carried out reliably.
A.2.14 Describe characteristics of a normalized database
-No Multi value attributes, -No partial dependency non-prime attributes depend on prime attributes, -Prime attributes are used to identify records. -No transitive dependency, when a non-prime attribute relies on another non-prime attribute
A.2.13 Differences between 1NF, 2NF, 3NF
1NF is one table 2NF is multiple tables that rely on primary keys 3NF Eliminates non-primary keys from relying on other non-primary keys
A.2.7 Explain the importance of a data definition language in implementing a data model
A DDL is a programming language used to define and create database schemas.
A.2.9 Define Composite Primary Key
A combination of more than one primary key to identify a record in a table or in a join
A.2.1 Define the term Relational Database Management System (RDBMS)
A database management system that is based on the relational model.
A.4.3 define the term data warehouse
A large collection of data accumulated from different resources within a company or country over a period of time. Used to guide decision making.
A.1.5 Define the term database transaction
A logical unit that is independently executed for data retrieval or updates.
A.2.5 Conceptual Schema
A model that contains entities and their relationship between them. It is a basic model for which the database will be built.
A.2.2 Retrieves Data
A record of data can be obtained via DBMS
A.4.10 Association Rules
A set of if and then statements that are used in uncovering relationships between two distinct sets of data. used to find customer behavior on a specific day
A.2.15 Yes/No
Boolean, only yes no, true false values
A.2.9 Define Secondary Key/Foreign Key
A unique key field which identifies a record in another table.
A.1.6 Explain concurrency in data sharing situations
Address conflicts with the simultaneous accessing or altering of data that can occur with a multi-user system
A.2.15 Hyperlink
Address that links to document or webpage
Updation Anomaly
An inconsistency in the data that happens after database is updated
A.4.10 compare the different forms of discovering patterns using data mining
Association Rules Classification Forecasting Cluster Analysis Data Matching
A.4.5 explain why data warehousing is time dependant
Because data collected at a certain time is usable for that time period. Data from 2005 is not going to be usable today.
A.4.11 describe situations that benefit from data mining
Can be used by banks to find fraudulent credit card use. Retailers can use to identify parts of the population most likely to respond to a particular advertisement.
A.2.9 Define Join
Collection of fields from more than one table rows based on a common primary key.
A.2.9 Define Field
Combination of one or more characters.
A.2.15 Evaluate the appropriateness of the different data types
Comparing the needs of users involved
A.2.6 Outline the Nature of the Data Dictionary
Contains data about each file in the database and each field within those files
A.2.2 Separates Data
DBMS serves as a filter between application programs and their associated data.
A.2.2 Protects Data
DBSM protects the data and relational elements from unauthorized users, physical damage, operating system failure, etc.
A.1.1 Differences in Data and Information
Data does not have a label stating what it is, information has a label that states what it is.
A.2.2 Integrates Data
Data is linked together so that it can be assembled into combinations during execution of particular applications.
A.2.2 Organizes Data
Data is organized or structured according to the specifications of the data definition language
A.3.8 Explain the difference between matching and data mining.
Data mining is the process of finding trends inside of one data warehouse. Data matching is finding trends across multiple data warehouses.
A.2.5 Logical Schema
Derived from the conceptual schema. Each entity in the conceptual schema is converted into either a table, field, or object with any restrictions needed.
A.2.18 Explain how a query can provide a view of a database
Don't know need to ask
A.3.7 Discuss the need for some databases to be open to interrogation by other parties
Dunno Need to ask
A.4.8 explain the need for ETL processes in data warehousing
ETL is used to add new data to the data warehouse. To EXTRACT is to collect data that are necessary to be stored in the data warehouse. Since data is from a variety of source all the data needs to be TRANSFORMED into one uniform format Once data is transformed it will be LOADED into the data warehouse for future use
A.4.9 describe how ETL processes can be used to clean up data for a data warehouse
Ensures that only high quality, and data relating to the purpose of the data warehouse in present within the warehouse.
A.2.3 Describe how DBSM can be used to promote data security
Features involving, data validation, access rights and data locking are all features that promote data security.
A.2.9 Define Record
Group of related fields
A.4.10 Cluster Analysis
Grouping sets of objects in such a way that objects in the same group are more similar. Supermarkets clusters, fruits in one place, meat in another, etc.
A.4.7 describe the advantages of using data warehousing
Improves data quality Provide a stable, centralized repository for large amounts of historical data. Improve business processes and decision-making with actionable insights.
A.1.2 Differences between information system and database
Information systems are a wider term than databases. As it refers to a complete system, where as a database is one part of a complete system.
A.2.11 Outline Issues Caused by Redundant Data
Insertion Deletion and update anomalies.
A.2.5 Physical Schema
It contains the name of the tables, list of fields in each table, relationships between tables that are specific to database management software.
A.2.15 Memo
Lengthy text Entries
A.2.15 Text
Letter, numbers, special characters
A.2.15 Date
Month, day. year, and sometimes time
A.2.15 Numeric
Numbers
A.2.15 Currency
Numbers containing decimals
A.2.10 Identify types of relationships within databases, One to Many
One row in table A may be linked with many rows in table B, but one row in table B is linked to only one row in table A.
A.2.2 Outline functions and tools of a DBMS
Organizes Data Integrates Data Separates Data Controls Data Retrieves Data Protects Data
A.3.6 Suggest methods to ensure the privacy of the personal data and the responsibility of those holding personal data not to sell or divulge it in any way.
Personal data management act or privacy act of the country or a company that ensures that data can be shared/ edited/ viewed only by authorized people.
A.2.15 Object
Photos, Videos, Audios
A.2.9 Define Candidate Key
Primary Key
A.4.10 Data Matching
Process of analyzing records of same individual/product in different resources. John's financial account with his data in income tax department to see whether he is paying his taxes or not.
A.1.9 Explain the Role of Data validation and data verification
Process of comparing data with a set of rules to find out if data is reasonable. Reduces data entry errors and enhance data integrity before program writes data on disk.
A.1.8 Describe 2 functions databases require to be preformed on them
Query functions, and update functions
A.2.12 Outline Importance of referential integrity in a normalized database
Referential integrity refers to the relationship between tables. It is important because it maintains the primary keys that are used to create a normalized database.
A.1.8 Query Functions
Request for specific data from a database. Query language consists of simple, English-like statements that allow users to specify data to display, print, or store Add, Delete, Update
A.3.1 Explain the role of a database administrator
Responsible for accurately and securely using, maintaining and developing computerized databases within a wide range of public and private sector organizations
A.3.3 Describe different methods of database recovery
Rollfoward, DBMS uses log to re-enter changes made to database since last save or back up Rollback, DBMS uses log to undo any changes made to database during a certain peroid of time
A.2.4 Define the term schema
Schema is a logical structure of data in the database. There are 3 stages of Schemas
A.2.8 Explain the importance of data modelling in the design of a database
Shows the rules and organization used that define how databases organize data. Defines how users view organization of data.
A.2.19 Describe the difference between a simple and complex Query
Simple queries are made using one table. Complex queries are made using multiple tables and complex conditions
A.1.3 Discuss the need for databases
Size of Data Ease of Updating Data Accuracy Security Redundancy Incomplete Data
A.2.1 Define the term Database Management System (DBMS)
System software for creating and managing databases.
A.2.2 Controls Data
The DBSM controls where data is physically stored. On data retrieval it locates and returns requested elements.
A.1.7 Durability
The guarantee that once the user has been notified of success, the transaction will persist, and not be undone. This means it will survive system failure, and that the database system has checked the integrity constraints and won't need to abort the transaction.
A.3.4 Outline how integrated database systems function
The integrated database is organized logically as a set of relations. The attributes of relations can assume the data type "picture" in addition to the alphanumerical data types to take care of picture data.
A.4.13 explain the nature of database segmentation
The partitioning of a database according to some feature in common in the rows.
A.2.9 Define Table
The place where records and fields are stored
A.1.7 Atomicity
The transaction property that notifies all other properties that something has failed
A.4.14 explain the nature and purpose of link analysis
The use of rules to establish associations between individual records in a data set
A.1.4 Describe the use of transactions states and updates to maintain data constancy
Transaction states ensure that data being transferred is correct and no inconsistent data is transferred. This ensures that data consistency is maintained.
A.2.9 Define Primary Key
Unique key which identifies a record in the table
A.2.15 AutoNumber
Unique number automatically assigned to each new record
A.1.8 Update Functions
Updates the database this could add more storage to the database, or add new function.
A.4.4 describe a range of situations suitable for data warehousing
Used to report the weather based on what has happened in similar times in the past by using a data warehouse the weather can be predicted.
A.3.5 Outline the use of databases in areas such as stock control, police records, health records, employee data
Used to store and access records that any f the fields have, such as criminal records, health records, and employee records. Databases would be one of the few storage methods that could be used in order to store all the different records.
A.4.6 describe how data in a warehouse is updated in real time
Warehouses update anytime a transaction happens,
A.2.10 Identify types of relationships within databases, One to One
When each record in one table is linked to only one record in the other table.
A.2.10 Identify types of relationships within databases, Many to Many
When one or more items in one table can have a relationship to one or more items in another table
A.2.20 Outline the different methods that can be used to construct a query
Writing SQL statements
Insertion Anomaly
adding new rows forces user to create duplicate data
Deletion Anomaly
deleting rows may cause a loss of data that would be needed for other future rows
A.4.15 describe the process of deviation detection
the detection of outlying data can be subjected to statistical techniques in order to identity unusual events or data subsets.
A.4.12 describe how predictive modeling is used
the determination of values for rows of a database. useful for predictions.
