1. What is Structured Query Language (SQL)? Explain the basic SQL operations used to interact with relational databases Using examples, Discuss the differences between SELECT, INSERT . UPDATE, and DELETE commands." 2. Explain the key SQL commands used to manage and manipulate data in relational databases. Discuss the differences between DDL, DML, and DCL , commands, and provide examples for each. 3. Explain "database data recovery", why is it important? Explain the different types of database recovery techniques , including backup-based recovery and transaction log-based recovery . Analyze the advantages and limitations of each approach. 4. What are distributed database systems?Describe the key characteristics and advantages of distributed databases. Discuss the challenges involved in managing distributed databases and the methods used to address these challenges. 5. Describe "object database systems" Explain their key features and advantages over relational database systems. Discuss the challenges in implementing object databases and provide examples of applications that benefit from using object-oriented databases. 6. What are report writers in databases, explain their role in database management systems, and discuss the key features and advantages of using report writers. Provide examples of applications where report writers are commonly used and describe how they improve the process of generating reports. 7. What is a database transaction? Explain the key properties of a transaction in a database management system (DBMS). Discuss the importance of transaction management and the techniques used to ensure the consistency and integrity of transactions in a multi-user environment. 8. What are data security and data integrity in the context of databases?Explain the importance of both in database management systems. Discuss the key techniques used to ensure data security and integrity, and describe the challenges in maintaining them.

1. Structured Query Language (SQL) is a standard programming language used to manage and manipulate relational databases. The basic SQL operations used to interact with relational databases include SELECT, INSERT, UPDATE, and DELETE. The SELECT command is used to retrieve data from a database table based on specific criteria. The INSERT command is used to add new data to a table. The UPDATE command is used to modify existing data in a table. The DELETE command is used to remove data from a table. The differences between these commands are that SELECT retrieves data, INSERT adds data, UPDATE modifies data, and DELETE removes data.<br />2. The key SQL commands used to manage and manipulate data in relational databases include Data Definition Language (DDL), Data Manipulation Language (DML), and Data Control Language (DCL). DDL commands are used to define the structure of the database, such as creating tables and indexes. DML commands are used to manipulate the data in the database, such as inserting, updating, and deleting data. DCL commands are used to control access to the database, such as granting and revoking permissions. The differences between these commands are that DDL defines the structure of the database, DML manipulates the data, and DCL controls access.<br />3. Database data recovery is the process of restoring data from a database that has experienced some form of data loss. It is important because it ensures that the data is not permanently lost and can be recovered in case of a failure. There are two main types of database recovery techniques: backup-based recovery and transaction log-based recovery. Backup-based recovery involves restoring data from a backup copy of the database, while transaction log-based recovery involves restoring data from a transaction log that records all changes made to the database. The advantages of backup-based recovery are that it is simple and can be used for large-scale recovery, while the disadvantages are that it can be time-consuming and may not be suitable for all types of data loss. The advantages of transaction log-based recovery are that it is fast and can be used for small-scale recovery, while the disadvantages are that it can be complex and may not be suitable for all types of data loss.<br />4. Distributed database systems are databases that are spread across multiple computers or nodes. They have several key characteristics and advantages, including improved performance, increased availability, and better scalability. However, they also present several challenges, such as ensuring consistency and integrity of data, managing concurrency control, and handling communication and coordination between nodes. Methods used to address these challenges include replication, partitioning, and distributed transaction management.<br />5. Object database systems are databases that store data in the form of objects, which are instances of classes that represent real-world entities. They have several key features and advantages over relational database systems, including improved data modeling, better support for complex data types, and faster performance. However, they also present several challenges, such as ensuring consistency and integrity of data, managing concurrency control, and handling inheritance and polymorphism. Examples of applications that benefit from using object-oriented databases include financial systems, computer-aided design (CAD) systems, and multimedia databases.<br />6. Report writers are tools used in database management systems to generate reports from database data. They have several key features and advantages, including improved report generation speed, better formatting and layout options, and the ability to generate dynamic reports based on user input. They are commonly used in applications such as financial reporting, sales analysis, and inventory management. Report writers improve the process of generating reports by automating repetitive tasks, reducing errors, and providing a user-friendly interface for report generation.<br />7. A database transaction is a logical unit of work that consists of one or more database operations. It has several key properties, including atomicity, consistency, isolation, and durability. Atomicity ensures that a transaction is treated as a single, indivisible unit of work, consistency ensures that a transaction leaves the database in a consistent state, isolation ensures that a transaction is independent of other transactions, and durability ensures that a transaction's effects are permanent. Transaction management is important because it ensures that transactions are processed reliably and that the database remains in a consistent state. Techniques used to ensure the consistency and integrity of transactions in a multi-user environment include locking, two-phase commit, and transaction rollback.<br />8. Data security and data integrity are two important concepts in database management systems. Data security refers to the protection of data from unauthorized access, modification, or deletion. Data integrity refers to the accuracy and consistency of data. Both are important because they ensure that the data is protected from unauthorized access and that the data is accurate and consistent. Techniques used to ensure data security and integrity include access control, encryption, and data validation. Challenges in maintaining data security and integrity include ensuring that data is protected from unauthorized access, preventing data corruption, and ensuring that data is backed up and recoverable in case of a failure.