My virtual notes
By Maria Paula Guillaumet
After accumulating notebooks with my notes for years, I decided to make a virtual repository with my topics of interest. Here you can find a little of this and that.
Después de acumular por años cuadernos con mis notas, decidí hacer un repositorio virtual con mis temas de interés. Aquí podrán encontrar un poco de esto y aquello.
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SQL
Available notes
Basic example: alfajores.db
- Jupyter visualization (Version 27.04.20)
- Download Jupyter notebook (Version 27.04.20)
Observations
The example runs in Jupyter using the library sqlalchemy. Every jupyter cell represents a query in SQL.
If it is executed in a SQL environment, the first steps can be skiped and there is no need of ‘%%sql’ in every cell.
Information
SQL is a standardized programming language that’s used to manage relational databases and perform various operations on the data in them.
Basic elements
Relational database
A database is a set of data stored in a computer. This data is usually structured in a way that makes the data easily accessible.
A relational database is a type of database. It uses a structure that allows us to identify and access data in relation to another piece of data in the database.
Table
A relational database system contains one or more objects called tables. The data or information for the database are stored in these tables.
Tables are uniquely identified by their names and are comprised of columns and rows. Columns contain the column name, data type, and any other attributes for the column. Rows contain the records or data for the columns.
Query
SQL, abbreviation for Structured Query Language, is a standardized query language for requesting information from a database. In fact, outside of computing terminology, the words “query” and “question” can be used interchangeably.