TCS Plsql Developer Interview Questions, Process, and Tips

Temp table is a table created temporarily in memory. Temp variable is a variable that holds temporary data.

• Temp table is used to store data temporarily during a session

• Temp variable is used to hold temporary data that is not needed after a certain point

• Temp table and variable are created using the 'CREATE GLOBAL TEMPORARY' and 'DECLARE' statements respectively

• Example: CREATE GLOBAL TEMPORARY TABLE temp_table (id NUMBER...read more

A mutating table or mutating trigger occurs when a trigger tries to update a table that is currently being modified.

• Mutating table occurs when a trigger references the table that is being modified.

• It can happen when a trigger is fired by an INSERT, UPDATE, or DELETE statement on the table.

• This can lead to unpredictable results or errors, such as ORA-04091: table is mutating, trigger/function may not see it.

• To avoid mut...read more

Autonomous transaction is a separate transaction initiated by a parent transaction.

• It allows a subtransaction to commit or rollback independently of the parent transaction.

• It is useful for logging or auditing purposes.

• It can be created using the PRAGMA AUTONOMOUS_TRANSACTION statement.

• Example: A parent transaction updates a table, while an autonomous transaction logs the changes made.

• Example: An autonomous transaction ...read more

Cursors are used to retrieve and manipulate data from a database in PL/SQL.

• Cursors are like pointers to a result set, allowing us to fetch and process rows one by one.

• There are two types of cursors: implicit and explicit.

• Implicit cursors are automatically created by Oracle when executing a SQL statement.

• Explicit cursors are declared and used by the programmer.

• Explicit cursors provide more control and flexibility compar...read more

Triggers are database objects that automatically execute in response to certain events.

• Triggers can be used to enforce business rules, audit data changes, and maintain referential integrity.

• They can be defined to execute before or after an event, such as a row being inserted, updated, or deleted.

• Triggers can also be nested, meaning one trigger can execute another trigger.

• Examples of triggers include automatically updat...read more

Truncate removes all data, delete removes selected data.

• Truncate is faster than delete as it doesn't log individual row deletions.

• Truncate cannot be rolled back, delete can be.

• Truncate resets identity columns, delete doesn't.

• Truncate doesn't fire triggers, delete does.

• Truncate is a DDL operation, delete is a DML operation.

PL/SQL program to print numbers in descending order from 103 to 3

• Use a loop to iterate from 103 to 3

• Print each number in the loop

• Decrement the loop counter by 3 in each iteration

A procedure in PL/SQL is a named block of code that can be called and executed multiple times.

• Syntax: CREATE [OR REPLACE] PROCEDURE procedure_name [(parameter1 [mode1] datatype1 [, parameter2 [mode2] datatype2]...)] IS

• Difference between procedure and function: Procedures do not return a value, while functions return a value.

• Procedures are used to perform an action, while functions are used to calculate and return a val...read more

To find if two tables have similar data, compare the records in both tables using a join or a subquery.

• Use a join operation to compare the records in both tables based on a common column.

• If the tables have a primary key, you can join them on that key to check for similar data.

• Alternatively, you can use a subquery to compare the data in both tables and check for matching records.

• Consider using the MINUS operator to find...read more

HAVING is used to filter groups while GROUP BY is used to group rows based on a column.

• HAVING is used with GROUP BY to filter groups based on a condition

• GROUP BY is used to group rows based on a column

• HAVING is used after GROUP BY in a query

• GROUP BY is used before HAVING in a query

• Example: SELECT department, AVG(salary) FROM employees GROUP BY department HAVING AVG(salary) > 5000;

Case and decode are conditional expressions in PL/SQL used for data manipulation.

• CASE is used for conditional logic in SQL statements, while DECODE is used for conditional logic in SELECT statements.

• CASE is more flexible and can handle multiple conditions, while DECODE is limited to one condition.

• CASE can be used in both SQL and PL/SQL, while DECODE is specific to SQL.

• Example of CASE: SELECT CASE WHEN condition1 THEN r...read more

Primary key uniquely identifies each record in a table, while foreign key establishes a link between two tables.

• Primary key ensures uniqueness and cannot have null values

• Foreign key establishes a relationship between tables based on the primary key of another table

• Example of primary key: EmployeeID in an Employee table

• Example of foreign key: DepartmentID in an Employee table linking to DepartmentID in a Department tabl

Rank assigns unique ranks to each distinct row, while Dense Rank assigns consecutive ranks without gaps.

• Rank may have gaps in the ranking sequence, while Dense Rank does not.

• Rank assigns the same rank to rows with the same values, while Dense Rank assigns different ranks.

• Rank function is non-consecutive, while Dense Rank function is consecutive.

Procedures are used to perform an action, while functions return a value.

• Procedures do not return a value, while functions do.

• Functions can be called from SQL queries, while procedures cannot.

• Functions must return a value, while procedures do not necessarily have to.

No, a package body cannot be used without a package specification.

• A package body must always be associated with a package specification.

• The package specification defines the public interface of the package, while the package body contains the implementation details.

• Attempting to use a package body without a corresponding package specification will result in compilation errors.

Use a SQL query with GROUP BY and HAVING clause to find duplicate values in a database.

• Use GROUP BY clause to group the values that are duplicated.

• Use HAVING clause to filter out the groups that have more than one occurrence.

• Example: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > 1;

Group by and having clause are used together to filter groups based on specified conditions.

• Group by clause is used to group rows that have the same values into summary rows.

• Having clause is used to filter groups based on specified conditions.

• Example: SELECT department, AVG(salary) FROM employees GROUP BY department HAVING AVG(salary) > 5000;

Substr function extracts a substring from a string, while Instr function returns the position of a substring within a string.

• Substr function syntax: SUBSTR(string, start_position, length)

• Example: SUBSTR('Hello World', 7, 5) will return 'World'

• Instr function syntax: INSTR(string, substring)

• Example: INSTR('Hello World', 'World') will return 7

Writing a SQL query with a subquery involves nesting one query inside another to retrieve specific data.

• Start by writing the main query that will retrieve the primary data

• Identify the criteria for the subquery to filter the results

• Enclose the subquery within parentheses and use it in the WHERE or FROM clause of the main query

• Ensure that the subquery returns a single value or a single column result

Char is fixed length, varchar is variable length with max 4000 bytes, varchar2 is variable length with max 32767 bytes.

• Char is fixed length and always right-padded with spaces, while varchar and varchar2 are variable length.

• Varchar can store up to 4000 bytes of data, while varchar2 can store up to 32767 bytes.

• Char is less efficient in terms of storage compared to varchar and varchar2.

No, it is not possible to combine two tables with differing data and columns without utilizing joins.

• Joins are necessary to combine tables based on a common column or key.

• Different data and columns require a join to match and merge the data properly.

• Examples of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

Yes, it is possible to update data in a view using INSTEAD OF triggers.

• Views are virtual tables that display data from one or more tables.

• By using INSTEAD OF triggers, you can update data in a view by specifying the logic to handle the update operation.

• The trigger intercepts the update operation on the view and executes the specified logic to update the underlying tables.

• For example, you can create an INSTEAD OF trigge...read more

TCS is a global IT services company known for its innovative solutions and commitment to employee growth.

• TCS has a strong reputation in the IT industry for delivering high-quality services.

• TCS offers opportunities for professional growth and development through training programs and career advancement.

• TCS has a diverse and inclusive work culture that values teamwork and collaboration.

A dynamic cursor in database management allows for the execution of different SQL queries at runtime.

• Dynamic cursors are used when the SQL query to be executed is not known until runtime.

• They allow for flexibility in querying the database based on user input or other conditions.

• Dynamic cursors can be used to handle varying result sets or conditions in a more efficient manner.

• Example: Using a dynamic cursor to search fo...read more

Yes, I have performed performance tuning by identifying bottlenecks and optimizing queries.

• Identified slow queries using tools like SQL Trace, Explain Plan, and AWR reports.

• Optimized queries by adding indexes, rewriting SQL statements, and reducing unnecessary data retrieval.

• Tuned PL/SQL code by using bulk processing, minimizing context switches, and optimizing loops.

• Utilized database features like partitioning and mat

A package in PL/SQL is a collection of related procedures, functions, variables, and other constructs.

• A package consists of two parts: package specification and package body.

• The package specification defines the public interface of the package, including declarations of variables, constants, cursors, procedures, and functions.

• The package body contains the actual implementation of the procedures and functions declared i...read more

I am excited about the opportunity to work with a global leader like TCS and contribute to innovative projects.

• TCS is a renowned global company with a strong reputation in the IT industry

• I am impressed by TCS's commitment to innovation and cutting-edge technology

• I believe TCS offers great opportunities for professional growth and development

• I am excited about the chance to work on diverse and challenging projects at TC

I prefer to discuss my salary expectations based on the responsibilities and requirements of the position.

• Focus on discussing salary expectations based on the job responsibilities and requirements.

• Avoid disclosing specific current salary package.

• Emphasize the importance of fair compensation based on market rates and skills.

• Provide examples of successful projects or achievements that demonstrate your value.

• Discuss oppor...read more

I am looking for a competitive salary package based on my experience and skills.

• I am open to discussing salary based on the responsibilities and requirements of the role.

• I have researched the average salary range for Plsql Developers in this location.

• I am looking for a package that includes benefits such as healthcare, retirement plans, and professional development opportunities.

Yes, I am comfortable with shift work and have experience working various shifts.

• I have previous experience working different shifts in my current/previous roles.

• I am flexible with my schedule and can easily adapt to changing shift patterns.

• I understand the importance of shift work in ensuring 24/7 coverage for critical systems.

Yes, I am open to any location for the Plsql Developer position.

• I am willing to relocate for the right opportunity

• I am open to working in different cities or countries

• I am flexible with travel requirements for the job

The GROUP BY clause in SQL is used to group rows that have the same values into summary rows.

• It is used with aggregate functions like COUNT, SUM, AVG, etc.

• It is used to group rows based on one or more columns in a table.

• It is often used in conjunction with the SELECT statement.