Database is nothing but an organized form of data for easy access, storing, retrieval and managing of data. This is also known as structured form of data which can be accessed in many ways. Example: School Management Database, Bank Management Database.

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A table is a set of data that are organized in a model with columns and rows. Columns can be categorized as vertical, and Rows are horizontal. A table has specified number of column called fields but can have any number of rows which is called record. Example: Table: Employee. Fields: Emp ID, Emp Name, Date of Birth Record: 201456, Alan, 11/13/1960

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A Database Management System (DBMS) is a program that controls creation, maintenance and use of a database. DBMS can be termed as File Manager that manages data in a database rather than saving it in file systems.

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RDBMS stands for Relational Database Management System. RDBMS store the data into the collection of tables, which is related by common fields between the columns of the table. It also provides relational operators to manipulate the data stored into the tables.

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SQL stands for Structured Query Language , and it is used to communicate with the Database. This is a standard language used to perform tasks such as retrieval, updation, insertion and deletion of data from a database.

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The DataSource interface provides an alternative to the DriverManager for making a connection. It makes the code more portable than DriverManager because it works with JNDI and it is created, deployed and managed separately from the application that uses it. If the DataSource location changes, then there is no need to change the code but change the...

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Prepared statements offer better performance, as they are pre-compiled. They reuse the same execution plan for different arguments rather than creating a new execution plan every time. Prepared statements use bind arguments, which are sent to the database engine. This allows mapping different requests with same prepared statement but different argu...

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Normalization is a design technique that is widely used as a guide in designing relational databases. Normalization is essentially a two step process that puts data into tabular form by removing repeating groups and then removes duplicated data from the relational tables (Additional reading recommended). Redundant data wastes disk space and creates...

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I have setup Step by Step Video Blog for understanding the PHPMyAdmin tool for MySQL. This is a Free tool for practicing MySQL for beginners as well as advanced users. The Video Covers the below topics. Download and Install Wamp Server. Setting up phpMyAdmin for MySQL. Changing Default user credentials in phpMyAdmin. Setting up MySQL DB. Exploring ...

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To select the nth highest record from a database, one need to do following steps: First, get the n highest records and sort them in ascending order. The nth highest record will be the last record in the result set. Then sort the result set in descending order and get the first one. Now let us write a query for step 1: SELECT * FROM na...

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Group is always associated with more than one entity with same value or interest. In MySQL, GROUP BY clause is used in similar terms to fetch records that have same value. GROUP BY clause can be used in the SELECT statement and can also be used with aggregate functions. Let us first see comman syntax for a group by query : SELECT col_names from t...

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JOIN is a term used to co-relate or combine two things related to each other, similarly in MySQL when two or more tables are co-related to each other with identifiers we use JOIN clause to retrieve records from them.  There are mainly three types of MySQL joins: MySQL INNER JOIN, also known as SIMPLE JOIN. MySQL LEFT OUTER JOIN, also known as LEFT ...

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It is possible to embed a SQL statement within another. When this is done on the WHERE or the HAVING statements, we have a subquery construct. What is subquery useful for ? It is used to join tables and there are cases where the only way to correlate two tables is through a subquery. SELECT emp.firstname, emp.surname FROM employees emp WHERE emp....

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Both primary key and unique key enforce uniqueness of the column on which they are defined. But by default Primary key creates a clustered index on the column. Unique creates a non-clustered index by default. Another major difference is that: Primary key doesnot allow NULLs. Unique key allows one NULL only. What is the best practice relating to pri...

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