Database SQL
Table - answer Has rows and columns, like those in a spreadsheet
Rows - answer Has data about a particular thing. Because rows record dara from a particular instance , rows are also know as records.
Column - answer Stores a characteristic common to all rows
SorrogateKey - answer are the ones which are automatically generated and assigned in the database
Composite key - answer When more than one column in a table must be combined to form a primary key
Foreign key - answer Provides the link between two tables. it creates a relationship between two tables
How does a data base store data - answer A relational database store data in tables,
and they represent the relationships among the rows of those tables
which ones are the principal components in a databse system - answer A database system is typically defined to consist of four components. users, the database application, the database managemente system (DBMS), and the database
What is a database management system - answer Is a computer program used to create, process, and administer the database. The DBMS receives requests encoded in
SQL and translates those requests into actions on the database
what is a database application - answer Is a set of programs that serves as an intermediarybetween the user and the DBMS
Which are the functions of a DBMS - answer create a database, create tables, create
supporting structures (indexes), modify (insert, update, or delete) database data, read database data, mantain database structure, enforce rules, control concurrency and perform backup and recovery
what is a referential integrity constraint - answer Are rules about the data Why a database is selfdescribing - answer databases also contains data that describes user data. Such descriptive data is called metadata because is data about data
what is a data warehouse - answer these are databases systems that have data, programs, and personnel that specialize in the preparation of data or BI processing
SQL was developed by whom - answer was developed by IBM in the late 70
which is one of the most important improvements in the sql - answer the standardization of the instead of trigger
name the five most important categories for the SQL statements - answer Data definition language (DDL), Data manipulation language (DML), SQL Persistent stored modules(SQLPSM), Transaction control language(TCL), Data control language(DCL)
DDL - answer Data definition language, statements,which are used for creating tables, relationships, and other structures
DML - answer Data Manipulation Language, statements, which are used for querying, inserting, modifying, and deleting data
PSM - answer Persistent Stored Modules, statements, Which extend SQl by adding procedural programming capabilities, such as variables and flow of control statement, that provide some programmability within the SQL framework
TCL - answer Transaction Control Language, statements,which are used to mark transaction boundaries and control transaction behavior
DCL - answer Data Control Language, statements, which are used to grant database
permissions (or to revoke those permission) to users and groups, so that the users or groups can perform various operations on the data in the database
what is the use of the wildcard character - answer is a shorthand notation for querying all of the columns of the table
What are the 5 standard operation on the SQL? - answer Count(*), SUM, AVG, MIN and MAX.
Count (*) - answer Is a predefined function, counts the number of rows on a table
Count{name} - answer Counts the number of rows on a table in where column {name} is not NULL
SUM - answer Calculate the sum of all values (numeric columns only)