Types of Computer Failures Database failures can usually be categorized into transaction, system, or media failures. Failed transactions in the middle of the execution can occur for many reasons, as described by Elmasri & Navathe (2015). Most Common Failures: The most common failures are described as computer …
Read MoreDescribe how disaster recovery from catastrophic failures is handled. Illustrate in detail Catastrophes can be broken down into two subcategories: physical problems and catastrophes. Physical catastrophes can be air conditioner failures, power issues, fire, or hacking attacks. Catastrophic errors are usually caused by …
Read MorePreventive Measures Against SQL Injection Attacks An SQL injection attack occurs by having an attacker inject a string input into the application; these changes or manipulate the SQL statement to the attacker’s advantage, as described by Elmasri & Navathe (2015). They indicate that an SQL injection attack inflicts …
Read MoreWhat Is Meant by the Closure of a Set of Functional Dependencies? A functional dependency is a one-way dependency between two attributes at any given time. For a unique attribute of value A there is one value of the attribute B associated with it through the relation. Even if the values for the attribute change, there …
Read MoreThe Reasons For Having Variable-Length Records And The Use Of Separator Characters There may be many reasons for a file having variable-length records, as described by Elmasri & Navathe (2015). They are described as one field that may need to be a varying size, a field that may contain a repeating group or value, a …
Read MoreUnderstanding Database Anomalies - Insertion, Deletion, and Modification
Insertion, Deletion, and Modification Anomalies Are Considered Bad An insertion anomaly is a situation that arises when one is prevented from inserting data into a relation because the complete primary key is not available. No part of a primary key can be null. Harrington (2009) points out that insertion anomalies …
Read MoreDemystifying SQL Retrieval Queries A Step-by-Step Breakdown
Feb 15, 2024 · 4 min read · database-programming sql-tutorial data-management relational-databases ·How Is SQL Query Retrieved, and Conceptually, What Is The Order oF Executing Each of The Six Clauses? SQL or the Structured Query Language described by Bowman, Emerson, & Darnovsky (1997) was proposed in 1970 by Dr. E. F. Codd at IBM and developed the SQL language over the next decade at research facilities and …
Read MoreHow Does One Choose Between the SQL Right Join Inner vs. Outer in SQL? An SQL Join is an operation of accessing the data from two or more tables or relations. In simple terms, a join occurs whenever multiple tables or relations appear in the FROM clause of a query, as described by Bhanuprakash, Nijagunarya & …
Read MoreUnveiling Attribute & Relationship Inheritance in EER Diagrams
Feb 13, 2024 · 3 min read · database-programming sql-tutorial data-management relational-databases ·The Mechanism of Attribute/Relationship Inheritance and Why it Useful The enhanced entity-relationship (EER) diagram includes the principles of the entity-relationship diagram with the addition of some other concepts as described by Tupper (2011). The additional concepts include subclasses and superclasses, …
Read MoreMapping EER Model Constructs to Relations in Your Database
Feb 10, 2024 · 3 min read · database-modeling data-management relational-theory database-programming relational-databases ·The Options for Mapping EER Model Constructs to Relations There are many ways of mapping the constructs from the EER model into the relational model. There are mapping of specializations or generalizations, shared subclasses, or multiple inheritance and categories. Several options are available for mapping several …
Read More