Pl sql developer interview questions and answers
Best PL/SQL Interview Questions & Answers.To defend against power loss, transactions (or their effects) must be recorded in a non-volatile memory. In a relational database, for instance, once a group of SQL statements execute, the results need to be stored permanently (even if the database crashes immediately thereafter).
Durability means that once a transaction has been committed, it will remain so, even in the event of power loss, crashes, or errors. if it uses strict - as opposed to relaxed - serializability), the effects of an incomplete transaction might not even be visible to another transaction. Depending on concurrency control method (i.e. Providing isolation is the main goal of concurrency control. The isolation property ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially, i.e., one after the other. Any data written to the database must be valid according to all defined rules, including constraints, cascades, triggers, and any combination thereof. The consistency property ensures that any transaction will bring the database from one valid state to another. An atomic system must guarantee atomicity in each and every situation, including power failures, errors, and crashes. Atomicity requires that each transaction be “all or nothing”: if one part of the transaction fails, the entire transaction fails, and the database state is left unchanged. How can you say that Database testing is different from that of GUI testing?ĪCID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably.What do you understand by explicit cursors?.What is returned by the cursor attribute SQL%NOTFOUND?.What do we need to check in Database Testing?.What do you mean by query optimization?.What is the difference between char and varchar2?.What is the difference between the RANK() and DENSE_RANK() functions? Provide an example.Can a View be active if the Base table is dropped?.Can a Stored Procedure contain a return value?.Does the data stored in the stored procedure increase access time or execution time? Explain.List some case manipulation functions in SQL.List the ways in which Dynamic SQL can be executed?.
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How to select unique records from a table?.Which operator is used in query for pattern matching?.What are aggregate and scalar functions?.What is the difference between TRUNCATE and DROP statements?.What is Union, minus and Interact commands?.What is Online Transaction Processing (OLTP)?.Advantages and Disadvantages of Stored Procedure.What are all different types of collation sensitivity?.What are all types of user defined functions?.What is the difference between Cluster and Non-Cluster Index?.What is the difference between SQL and MySQL?.What is the difference between SQL and PL/SQL?.