# Data

34 Data terms explained simply, ordered from basic to advanced. Start at the top if the topic is new to you.

## Basic

- [Backup](https://tidbit.legios.com.ar/backup/): A separate copy of your data, kept so you can get it back when the original is lost.
- [Big data](https://tidbit.legios.com.ar/big-data/): Data so large, fast or messy that one ordinary computer cannot handle it.
- [Business intelligence](https://tidbit.legios.com.ar/business-intelligence/): Turning a company's data into reports and dashboards people use to decide.
- [CSV](https://tidbit.legios.com.ar/csv/): A plain text file that holds a table: one row per line, commas between values.
- [Data cleaning](https://tidbit.legios.com.ar/data-cleaning/): Fixing errors, gaps and duplicates in data before anyone trusts it.
- [Data science](https://tidbit.legios.com.ar/data-science/): Using statistics, code and business sense to answer questions with data.
- [Database](https://tidbit.legios.com.ar/database/): An organized store of data that programs can search and update safely.
- [Metadata](https://tidbit.legios.com.ar/metadata/): Data that describes other data: who made it, when, where and what it contains.
- [Oracle](https://tidbit.legios.com.ar/oracle/): The company behind one of the most used business databases, now also a cloud provider.
- [SAP](https://tidbit.legios.com.ar/sap/): The German company whose software runs the back office of many large businesses.
- [Spreadsheet vs database](https://tidbit.legios.com.ar/spreadsheet-vs-database/): Why a company that runs on Excel eventually needs a real database.
- [SQL](https://tidbit.legios.com.ar/sql/): The language you use to ask a database questions.
- [XML](https://tidbit.legios.com.ar/xml/): A text format that wraps data in named tags, so both people and programs can read it.

## Intermediate

- [Amazon Athena](https://tidbit.legios.com.ar/amazon-athena/): Run SQL directly on files sitting in S3, with no database to set up.
- [Amazon OpenSearch Service](https://tidbit.legios.com.ar/amazon-opensearch-service/): Managed search engine on AWS, for site search boxes and digging through logs.
- [Amazon Redshift](https://tidbit.legios.com.ar/amazon-redshift/): AWS's data warehouse: SQL over huge tables, built for analysis rather than apps.
- [AWS Glue](https://tidbit.legios.com.ar/aws-glue/): AWS's service for finding, describing and cleaning up data, with no servers to run.
- [Data catalog](https://tidbit.legios.com.ar/data-catalog/): A searchable inventory of an organization's datasets, with what each one means.
- [Data governance](https://tidbit.legios.com.ar/data-governance/): The rules and roles that decide who owns data, who can use it and how it is kept right.
- [Data lake](https://tidbit.legios.com.ar/data-lake/): Cheap storage where all your data is kept as raw files, to be sorted out later.
- [Data warehouse](https://tidbit.legios.com.ar/data-warehouse/): A database built for analysis: years of history, from many sources, in one place.
- [Database index](https://tidbit.legios.com.ar/database-index/): A sorted shortcut that lets a database find rows without reading the whole table.
- [Database schema](https://tidbit.legios.com.ar/database-schema/): The blueprint of a database: which tables exist, their columns and how they connect.
- [ETL](https://tidbit.legios.com.ar/etl/): Copy data out of its sources, clean it up, load it where it can be analyzed.
- [NoSQL](https://tidbit.legios.com.ar/nosql/): Databases that store data in shapes other than tables with fixed columns.
- [Primary and foreign keys](https://tidbit.legios.com.ar/primary-and-foreign-keys/): A primary key names each row uniquely; a foreign key points to a row in another table.
- [SQL injection](https://tidbit.legios.com.ar/sql-injection/): Typing text into a form that the database mistakes for its own instructions.
- [Vector database](https://tidbit.legios.com.ar/vector-database/): A database that finds things by similar meaning instead of exact matching words.

## Advanced

- [Apache Spark](https://tidbit.legios.com.ar/apache-spark/): An open source engine that splits work on huge datasets across many machines.
- [Data mesh](https://tidbit.legios.com.ar/data-mesh/): An organizational approach where each business team owns and publishes its own data.
- [Data streaming](https://tidbit.legios.com.ar/data-streaming/): Processing data as a continuous flow of events, seconds after they happen.
- [dbt](https://tidbit.legios.com.ar/dbt/): A tool for writing data transformations as SQL files, with tests and docs, like software.
- [OLAP and OLTP](https://tidbit.legios.com.ar/olap-and-oltp/): Two kinds of database work: many small transactions, or a few huge analytical questions.
- [Parquet](https://tidbit.legios.com.ar/parquet/): A file format that stores tables by column, compressed, so analytics reads far less.