Oracle SQL & PL/SQL

  In Oracle Database, DBMS_SCHEDULER is a powerful built-in PL/SQL package used to schedule, automate, execute, and monitor database tasks along with manage background task inside the Oracle Database. It is especially useful for DBAs who need to automate routine maintenance, data processing, backups, reporting, and other recurring activities. 1. What is DBMS_SCHEDULER and it's use. DBMS_SCHEDULER is an Oracle-supplied PL/SQL package that allows database users and administrators to define and manage scheduled jobs. For example, suppose a DBA needs to run a table cleanup procedure every day at 2:00 AM. Instead of manually executing the procedure, the DBA can create a scheduler job that runs automatically. Automating data loads, transformations and clean up from staging tables into core datawarehouse tables.  Data purging activities Report scheduling

  A database schema is like a blueprint that defines how data is organized and stored in a database . It describes the structure of tables, columns, data types, relationships, constraints, and indexes, providing a clear framework for how different pieces of data are stored and connected. 🔑 Key Points Schema = Structure → Defines tables, columns, and rules. Ensures consistency → Data must follow the schema (e.g., a column defined as INT cannot store text). Relationships → Specifies how tables connect (foreign keys, primary keys). Constraints → Rules like NOT NULL , UNIQUE , CHECK .

SQL databases are relational and structured, making them ideal for applications that require well-defined relationships, data consistency, and reliable transactions. NoSQL databases , on the other hand, are non-relational and offer greater flexibility, making them well-suited for handling large volumes of rapidly changing, semi-structured, or unstructured data. In simple terms: Choose SQL when data relationships, accuracy, and transactional integrity are critical. Choose NoSQL when you need flexibility, high scalability, and fast performance for large or evolving datasets.  📌 When to Use SQL Transactional systems : Banking, e-commerce checkout, payroll. Complex queries & reporting : Business intelligence, analytics dashboards. Stable schema : Customer records, inventory management. Strong consistency required : Financial transactions, compliance-heavy industries. 📌 When to Use NoSQL High scalability needs : Social media feeds, IoT sensor data, gaming leaderboards. Unstru...

About Oracle Buffer :- All Commands of SQL are typed at the SQL prompt. Only one SQL statement is managed in the SQL buffer. The current SQL statement replaces the previous SQL statement in the buffer. The SQL statements can be divided into different lines within the SQL buffer. Only one line i.e, the current line can be active at a time in the SQL buffer. At SQL prompt, editing is possible only in the current SQL buffer line. Every statement of SQL should be terminated using semi colon " ; ". One sql statement can contain only one semi colon. To run the previous or current SQL statement in the bufer type " / " at SQL prompt. To open the SQL editor type " ED " at SQL prompt.