Structured Query Language

20/06/2017

If you’ve heard of certain opinions about it, it’s a good thing to win, it’s true. A start in this area should be by learning SQL. To explain what this term means, we’ll talk about how we can interact with certain information: products, files, and so on. This information will not be stored in an application, but in a particular system with which this application works, that is, a database. The special language that communicates with the database is called SQL, ie Structured Query Language.
Why do we need SQL? Simple: We can make tables where we can store information, modify or delete information from these bases, control access to certain information.
The most known and used application is 3Terrier because it is distributed in 3 areas, namely:
1. Database
2. server
3. GUI means what the browser uses or where it is accessing.
All things happen in a database. The relational database is a system where some Excel-like tables are stored. There are certain relationships between the tables, hence the relational database name.
The SQL language is the closest to human language and then it is the best start in an IT career.
A business analyst wins very well. In order to activate in the IT field on this function, if they worked in finance or other fields, they will be able to use the knowledge they already had. This feature deals with translating requirements for the software application that that company uses. He must learn how to implement these applications in the company’s database. For this, it needs SQL.
The most common database you can use is the Oracle database. The applications of this database are free, and the simple variants have a free license, including for commercial purposes. The start is done with Oracle Database Express Edition and Oracle SQL developer, which you can download and install.
To use an Oracle database, we need to understand how it works, how data is stored, how it can be accessed, how we can access data, etc.
The language includes: indexes, views, functions, tables, types, partitions. There are some terms that will be used in IT.
By the term Oracle joined, we understand how to tie some tables together. DML Instructions show us how to delete or modify information, by entering TCL instructions into the database, modifying or canceling.
DDL allows some people to access the information.
With Primary Key, Not Null, Check, Foreign Key, Unique, Default Values, we can implement the validation rules, the basic information to be correct.
With Conecct By, Cube, Roolup, With, Case, you can do special SQL constructions.
When things do not work properly, we can use SQL Tuning Basics through: Indecision, Tables Stats, SQL Query Execution Plan, Hints.
PL-SQL Fundamentals is an extension of SQL.
All of this will be applied between the clients of an institution, entering data, modifying them, deleting information, opening new accounts, attaching existing clients, transferring funds between clients’ accounts, listing information from the database.
We will analyze the requirements, choose a data design and solutions, create tables, views, indexes, SQL statements, packages, functions and test solutions.