reorganise course folders

courses/level101/databases_sql/intro.md

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+# Relational Databases
+
+### Prerequisites
+*   Complete [Linux course](https://linkedin.github.io/school-of-sre/level101/linux_basics/intro/)
+*   Install Docker (for lab section)
+
+### What to expect from this course
+You will have an understanding of what relational databases are, their advantages, and some MySQL specific concepts.
+
+### What is not covered under this course
+*   In depth implementation details
+
+*   Advanced topics like normalization, sharding
+
+*   Specific tools for administration
+
+### Introduction
+The main purpose of database systems is to manage data. This includes storage, adding new data, deleting unused data, updating existing data, retrieving data within a reasonable response time, other maintenance tasks to keep the system running etc.
+
+### Pre-reads
+[RDBMS Concepts](https://beginnersbook.com/2015/04/rdbms-concepts/)
+
+### Course Contents
+- [Key Concepts](https://linkedin.github.io/school-of-sre/level101/databases_sql/concepts/)
+- [MySQL Architecture](https://linkedin.github.io/school-of-sre/level101/databases_sql/mysql/#mysql-architecture)
+- [InnoDB](https://linkedin.github.io/school-of-sre/level101/databases_sql/innodb/)
+- [Backup and Recovery](https://linkedin.github.io/school-of-sre/level101/databases_sql/backup_recovery/)
+- [MySQL Replication](https://linkedin.github.io/school-of-sre/level101/databases_sql/replication/)
+- Operational Concepts
+    - [SELECT Query](https://linkedin.github.io/school-of-sre/level101/databases_sql/select_query/)
+    - [Query Performance](https://linkedin.github.io/school-of-sre/level101/databases_sql/query_performance/)
+- [Lab](https://linkedin.github.io/school-of-sre/level101/databases_sql/lab/)
+- [Further Reading](https://linkedin.github.io/school-of-sre/level101/databases_sql/conclusion/#further-reading)