To safely and thoroughly uninstall MySQL and clean all residual files, follow the following steps: 1. Stop MySQL service; 2. Uninstall MySQL packages; 3. Clean configuration files and data directories; 4. Verify that the uninstallation is thorough.

The main difference between MySQL and Oracle is licenses, features, and advantages. 1. License: MySQL provides a GPL license for free use, and Oracle adopts a proprietary license, which is expensive. 2. Function: MySQL has simple functions and is suitable for web applications and small and medium-sized enterprises. Oracle has powerful functions and is suitable for large-scale data and complex businesses. 3. Advantages: MySQL is open source free, suitable for startups, and Oracle is reliable in performance, suitable for large enterprises.

MySQL uses GPL and commercial licenses for small and open source projects; Oracle uses commercial licenses for enterprises that require high performance. MySQL's GPL license is free, and commercial licenses require payment; Oracle license fees are calculated based on processors or users, and the cost is relatively high.

In different application scenarios, choosing MongoDB or Oracle depends on specific needs: 1) If you need to process a large amount of unstructured data and do not have high requirements for data consistency, choose MongoDB; 2) If you need strict data consistency and complex queries, choose Oracle.

The key to learning Java without taking detours is: 1. Understand core concepts and grammar; 2. Practice more; 3. Understand memory management and garbage collection; 4. Join online communities; 5. Read other people’s code; 6. Understand common libraries and frameworks; 7. Learn to deal with common mistakes; 8. Make a learning plan and proceed step by step. These methods can help you master Java programming efficiently.

Learning Java requires learning basic syntax, object-oriented programming, collection frameworks, exception handling, multithreading, I/O streaming, JDBC, network programming, and advanced features such as reflection and annotation. 1. The basic syntax includes variables, data types, operators and control flow statements. 2. Object-oriented programming covers classes, objects, inheritance, polymorphism, encapsulation and abstraction. 3. The collection framework involves ArrayList, LinkedList, HashSet, and HashMap. 4. Exception handling ensures program robustness through try-catch block. 5. Multithreaded programming requires understanding of thread life cycle and synchronization. 6. I/O streams are used for data reading, writing and file operations. 7. JDBC is used to interact with databases. 8. Network programming passes S

The steps to connect to an Oracle database connection pool using JDBC include: 1) Configure the connection pool, 2) Get the connection from the connection pool, 3) Perform SQL operations, and 4) Close the resources. Use OracleUCP to effectively manage connections and improve performance.

To connect Oracle database to Tableau for data visualization, you need to follow the following steps: 1. Configure Oracle database connection in Tableau, use ODBC or JDBC drivers; 2. Explore data and create visualizations, such as bar charts, etc.; 3. Optimize SQL queries and indexes to improve performance; 4. Use Oracle's complex data types and functions to implement through custom SQL queries; 5. Create materialized views to improve query speed; 6. Use Tableau's interactive functions such as dashboard for in-depth analysis.