Info Man L

Information System (IS)

A system that provides data collection, storage, processing, and retrieval of data.

Systems Analysis

The process of determining the need for an information system and defining its scope.

Systems Development

The process of creating and implementing an information system.

Database Development

The process of database design and implementation.

SDLC (Systems Development Life Cycle)

A framework that traces the history and development of an information system.

Planning

SDLC phase that identifies company objectives and project goals.

Analysis

SDLC phase that examines problems and requirements in detail.

Detailed Systems Design

SDLC phase where system processes and structures are designed.

Implementation

SDLC phase where hardware, software, and databases are installed and deployed.

Maintenance

SDLC phase that includes corrective, adaptive, and perfective improvements.

DBLC (Database Life Cycle)

A framework that traces the history and development of a database.

Database Initial Study

DBLC phase that analyzes company situations, problems, objectives, and scope.

Database Design

DBLC phase where database structures and relationships are planned.

Implementation and Loading

DBLC phase where database structures are created and data is loaded.

Testing and Evaluation

DBLC phase that verifies database security, performance, and correctness.

Operation

DBLC phase where the database becomes fully functional and operational.

Maintenance and Evolution

DBLC phase involving database updates and improvements.

Conceptual Design

The first stage of database design that creates a database model independent of DBMS software.

Conceptual Data Model

A model that describes entities, attributes, relationships, and constraints.

Data Dictionary

A repository containing definitions of database objects.

Entity Relationship Modeling (ERM)

The process of identifying entities, attributes, relationships, and constraints.

Normalization

The process of organizing data to reduce redundancy and anomalies.

Module

An information system component that performs a specific business function.

Module Cohesivity

The strength of relationships among components within a module.

Module Coupling

The degree of dependency between modules.

Database Fragment

A subset of a database stored at a specific location.

Distributed Database Design

The process of allocating database fragments across multiple locations.

SQL (Structured Query Language)

The standard language used to manage relational databases.

DML (Data Manipulation Language)

SQL commands used to retrieve and modify data.

DDL (Data Definition Language)

SQL commands used to define database structures.

TCL (Transaction Control Language)

SQL commands used to manage transactions.

DCL (Data Control Language)

SQL commands used to manage database permissions.

SELECT

SQL command used to retrieve data from tables.

FROM

SQL clause that specifies the source table(s).

WHERE

SQL clause that filters rows based on conditions.

GROUP BY

SQL clause that groups rows with similar values.

HAVING

SQL clause that filters grouped results.

ORDER BY

SQL clause that sorts query results.

Alias

An alternative name assigned to a table or column.

Computed Column

A column whose value is derived from calculations.

Wildcard Character

A symbol used to represent unknown characters in searches.

DISTINCT

SQL keyword that returns only unique values.

Comparison Operator

A symbol used to compare values.

Equal To (=)

Operator used to test equality.

Not Equal To (<> or !=)

Operator used to test inequality.

Greater Than (>)

Operator used to test if a value is larger.

Less Than (<)

Operator used to test if a value is smaller.

BETWEEN

Operator used to check whether a value falls within a range.

IN

Operator used to check whether a value exists in a list.

LIKE

Operator used to perform pattern matching.

IS NULL

Operator used to check for null values.

AND

Logical operator requiring all conditions to be true.

OR

Logical operator requiring at least one condition to be true.

NOT

Logical operator that negates a condition.

JOIN

Operation used to combine rows from multiple tables.

Inner Join

Returns only matching rows from joined tables.

Outer Join

Returns matching rows plus unmatched rows.

Natural Join

Automatically joins tables using common attributes.

CREATE TABLE

SQL command used to create a table.

ALTER TABLE

SQL command used to modify a table structure.

DROP TABLE

SQL command used to delete a table and its data.

CREATE INDEX

SQL command used to create an index.

DROP INDEX

SQL command used to remove an index.

CREATE VIEW

SQL command used to create a virtual table.

Schema

A logical group of related database objects.

Constraint

A rule that restricts the values allowed in a column.

Primary Key

A column or set of columns that uniquely identifies a row.

Foreign Key

A column that references a primary key in another table.

NOT NULL

Constraint that prevents null values.

UNIQUE

Constraint that prevents duplicate values.

DEFAULT

Constraint that assigns a default value.

CHECK

Constraint that validates entered data.

INSERT

SQL command used to add rows to a table.

UPDATE

SQL command used to modify existing rows.

DELETE

SQL command used to remove rows from a table.

COMMIT

SQL command that permanently saves transaction changes.

ROLLBACK

SQL command that restores data to its previous committed state.

View

A virtual table based on a SELECT query.

Base Table

The actual table upon which a view is based.

Updatable View

A view that allows updates to underlying base tables.

Batch Update Routine

A process that updates multiple records in a single operation.

Transaction

A logical unit of work that must be completed entirely or aborted entirely.

Database Request

A single SQL statement executed within a transaction.

Consistent Database State

A state where all integrity constraints are satisfied.

Atomicity

ACID property requiring all transaction operations to succeed or fail together.

Consistency

ACID property ensuring the database remains valid before and after transactions.

Isolation

ACID property preventing transactions from interfering with one another.

Durability

ACID property ensuring committed changes are permanent.

ACID

Acronym for Atomicity, Consistency, Isolation, and Durability.

Serializability

Property ensuring concurrent transactions produce results equivalent to serial execution.

Transaction Log

A record of all database transactions used for recovery.

Concurrency Control

DBMS mechanism that manages simultaneous transactions while preserving integrity.

Lost Update Problem

Occurs when one transaction overwrites another transaction's update.

Uncommitted Data Problem

Occurs when a transaction accesses data that has not yet been committed.

Inconsistent Retrieval

Occurs when data changes while a transaction is reading it.

Scheduler

The DBMS component that determines the execution order of concurrent transactions.

Serializable Schedule

A schedule whose results match serial transaction execution.

Lock

A mechanism that reserves data for transaction use.

Lock Manager

The DBMS component responsible for assigning and enforcing locks.

Pessimistic Locking

Locking approach that assumes transaction conflicts are likely.