"Explain database" generally refers to a command or feature within a database management system (DBMS) that provides information about how a particular SQL query is executed by the database engine. It's commonly used to analyze the query execution plan, which outlines how the database will retrieve and process the data to fulfill the query. In the context of relational databases, when a query is submitted to the database, the DBMS evaluates various ways to access the data based on indexes, table sizes, and available statistics. The "explain" command allows users to see this evaluation process and understand the steps the database will take to execute the query. For instance, in MySQL, you would use the "EXPLAIN" keyword before your SELECT query to obtain the query execution plan. Here's a basic example: EXPLAIN SELECT * FROM your_table WHERE some_condition; The output of this command would provide insight into how the database plans to carry out the query, such as which indexes will be used, the join type, and the order of operations. Additionally, in PostgreSQL, you'd use the "EXPLAIN ANALYZE" command to not only see the query plan but also evaluate the actual execution time and other statistics. Here's an example: EXPLAIN ANALYZE SELECT * FROM your_table WHERE some_condition; This can be extremely useful in optimizing query performance by identifying potential bottlenecks, such as table scans or inefficient use of indexes. Overall, the "explain" functionality is a critical tool for database administrators and developers to understand and fine-tune the performance of their queries, especially in complex database environments. Does this cover the information you were looking for? If there's anything more specific you'd like to explore with regard to "explain database," feel free to share the details!