SQL Terms Flashcards
What is database?
Adatabase is an organized collection of data,stored and retrieved digitally from a remote or local computer system. Databases can be vast and complex, and such databases are developed using fixed design and modeling approaches
What is DBMS?
DBMS stands for database management system. DBMS is a system software responsible for the creation, retrieval, updating, and management of the database.it ensures that our data is consistent, organized, and is easily accessible by serving as an interface between the database and its end -users or application software.
What is RDBMS? How is it different from DBMS?
RDBMS stands for relational database management system. The key difference is that RDBMS stores data in the form of a collection of tables,and relations can be defined between the common fields of these tables
. Most modern database management systems like MySQL Microsoft SQL server, oracle, IBM DB2, Amazon red shift are based on RDBMS.
What is SQL?
SQL stands for structured query language.it is the standard language for relational database management systems.it is especially useful in handling organized data comprised or entities (variables) and relations between different entities of data.
What is the difference between SQL and MySQL ?
SQL is a standard language for retrieving and manipulatingstructured databases. On the contrary, my SQL is a relational database management system like SQL server, oracle or IBM DB2, that is used to manage SQL databases..
What are tables and fields?
A table is an organized collection of data stored in the form of rows and columns. Columns can be categorized as vertical and rows as horizontal.
What is data analysis?
The process of analyzing, modeling, and interpret data to draw insights or conclusions. From the insights informed decisions can be made.
Responsibilities of date analysts.
Collects and analyses data statistical techniques used
Interpret and analyzes trends or patterns in complex data sets
Find opportunities for improvement in existing processes or areas
Assist in data mining, data cleansing, and data storage structure
Key skills for data analyst
Critical thinking
Communication
Data visualization
SQL
Data analysis process
Assembling/collecting → cleaning → interpreting → transforming → modeling
What is data cleaning?
Identifying, and then modifying, replacing, or deleting the incorrect incomplete, inaccurate, irrelevant, or missing portions of the data as the need arises
Data mining vs. Data profiling
Data mining: analyzing data to find relations that were not previously discovered. Emphasis on finding unusual records, detecting dependencies, and analyzing clusters. Analyzing large datasets to determine trends and patterns in them.
Data profiling: analyzing data’s individual attributes. Emphasis on providing useful information on data attributes such as data types, frequency, etc. Discovery and evaluation of enterprise metadata.
Data validation
Field level validation:validates data as and when it is entered into the field.
Explain outlier
Values in a data set that differ significantly from the mean of characteristic features of a dataset.
Best detected through box plots or standard deviation methods.
Normal distribution
The bell curve. Defines and measures now the values of a variable differ
In their means and standard deviations,
