Oracle 1z0-149 Exam Dumps, 1z0-149 Practice Test Questions

Oracle 1z0-149 Exam Dumps & Practice Test Questions

Question 1

Which three statements accurately reflect how PL/SQL handles parameter passing in subprograms? (Choose three.)

A. If a subprogram raises an unhandled exception, PL/SQL still applies the final values to the actual parameters.
B. Parameters defined as IN cannot be reassigned within the subprogram body.
C. IN OUT parameters serve to both provide input values and return output results.
D. OUT parameters require variables to be passed as actual arguments.
E. IN parameters can be modified inside the subprogram like local variables.
F. OUT parameters are immutable inside the subprogram once initialized.
G. Constants or expressions can be passed to IN OUT parameters directly.

Correct Answer: B, C, D

Explanation:
In PL/SQL, parameters are used to pass values between the calling environment and subprograms (procedures or functions). There are three primary types of parameters: IN, OUT, and IN OUT. These dictate how the values are passed and modified within subprograms.

Let’s analyze the options:

A. If a subprogram raises an unhandled exception, PL/SQL still applies the final values to the actual parameters.
This is incorrect. If a subprogram raises an unhandled exception, the actual parameter values may not be updated as the changes are rolled back when the exception is raised. This means that final values might not be applied if the exception interrupts the subprogram execution.
B. Parameters defined as IN cannot be reassigned within the subprogram body.
This is correct. Parameters declared as IN are input-only and are read-only within the subprogram. They cannot be reassigned or modified inside the subprogram body.
C. IN OUT parameters serve to both provide input values and return output results.
This is correct. IN OUT parameters can be used to both pass an input value to the subprogram and return an output value back to the caller after execution. These parameters can be modified within the subprogram.
D. OUT parameters require variables to be passed as actual arguments.
This is correct. For OUT parameters, the actual arguments must be variables because the subprogram will be modifying the values of those variables to return results. You cannot pass constants or expressions to OUT parameters.
E. IN parameters can be modified inside the subprogram like local variables.
This is incorrect. IN parameters are input-only and cannot be modified within the subprogram. They are read-only.
F. OUT parameters are immutable inside the subprogram once initialized.
This is incorrect. OUT parameters are modifiable within the subprogram. They are meant to be used to return values to the caller, and their values can be set and changed inside the subprogram body.
G. Constants or expressions can be passed to IN OUT parameters directly.
This is incorrect. IN OUT parameters require variables to be passed, not constants or expressions. Constants or expressions cannot hold the output result.

Thus, the correct answers are B, C, and D.

Question 2

Which two statements correctly describe the role and behavior of the PLSQL_CODE_TYPE parameter in PL/SQL? (Choose two.)

A. Changing PLSQL_CODE_TYPE alters the compilation method of all already compiled PL/SQL units.
B. The system default for PLSQL_CODE_TYPE is NATIVE.
C. Setting PLSQL_CODE_TYPE to NATIVE compiles PL/SQL code into machine-dependent code.
D. Using the REUSE SETTINGS clause during recompilation preserves the original compilation configuration.
E. Setting PLSQL_CODE_TYPE to NATIVE compiles code into cross-platform bytecode.

Correct Answer: B, C

Explanation:
The PLSQL_CODE_TYPE parameter specifies how PL/SQL code is compiled. This can affect the execution performance of PL/SQL code, and it can be set to different values such as NATIVE or INTERPRETED.

Let’s break down the options:

A. Changing PLSQL_CODE_TYPE alters the compilation method of all already compiled PL/SQL units.
This is incorrect. Changing the PLSQL_CODE_TYPE parameter does not alter the compilation method of already compiled PL/SQL units. To recompile a unit with a different code type, you must manually recompile the unit.
B. The system default for PLSQL_CODE_TYPE is NATIVE.
This is correct. By default, Oracle uses NATIVE code for PL/SQL compilation, which means it compiles PL/SQL into machine-specific code that is faster to execute.
C. Setting PLSQL_CODE_TYPE to NATIVE compiles PL/SQL code into machine-dependent code.
This is correct. When the PLSQL_CODE_TYPE is set to NATIVE, PL/SQL code is compiled into machine-specific code, making it more efficient and faster during execution. This is in contrast to INTERPRETED code, which is not machine-dependent.
D. Using the REUSE SETTINGS clause during recompilation preserves the original compilation configuration.
This is incorrect. The REUSE SETTINGS clause is used to reuse settings when recompiling, but it does not directly relate to the PLSQL_CODE_TYPE setting. It preserves settings related to other options, but it is not relevant to code type selection.
E. Setting PLSQL_CODE_TYPE to NATIVE compiles code into cross-platform bytecode.
This is incorrect. Setting the PLSQL_CODE_TYPE to NATIVE compiles the code into machine-dependent code, not cross-platform bytecode. The INTERPRETED setting would be more aligned with bytecode compilation.

Thus, the correct answers are B and C.

Question 3

In which three SQL operations does the use of a variable declared with %ROWTYPE offer the greatest benefit within PL/SQL blocks? (Choose three.)

A. CREATE – for defining new database objects like tables or procedures
B. DROP – for removing schema-level objects such as tables or indexes
C. UPDATE – for modifying one or more fields in a row
D. SELECT – for retrieving a complete row from a table
E. DELETE – for removing records from a table
F. ALTER – for modifying the structure of existing database objects
G. INSERT – for adding full rows to a table

Correct Answers: C, D, G

Explanation:
The %ROWTYPE attribute in PL/SQL is a powerful feature used to declare a record variable that has the same structure as a row in a database table or a cursor. This feature becomes extremely beneficial in operations where entire rows of data are being manipulated — such as when you retrieve, insert, or update all or most of the columns of a row.

Let’s explore why C, D, and G are correct:

C (UPDATE): When updating one or more fields in a table, using a variable declared with %ROWTYPE allows you to work with a record that mirrors the structure of a table row. You can load the entire row into a %ROWTYPE variable, modify only the fields of interest, and then perform the update. This approach reduces code verbosity and enhances maintainability.
D (SELECT): This is one of the primary use cases for %ROWTYPE. When you need to fetch all columns from a table, using %ROWTYPE allows you to write SELECT * INTO row_variable FROM table WHERE condition. This eliminates the need to individually declare variables for each column and manually map them, which is particularly useful when working with tables that have many columns.
G (INSERT): When inserting a complete row into a table, having a %ROWTYPE variable lets you populate the fields easily and pass the entire record to the INSERT statement. For example: INSERT INTO table_name VALUES row_variable;. This method ensures that all fields align with the table definition, reducing the risk of errors due to column mismatch.

Now, let’s consider why the other options are incorrect:

A (CREATE): The CREATE operation is a Data Definition Language (DDL) operation used to define new objects such as tables, indexes, and procedures. It does not deal with row-level data manipulation and thus does not benefit from %ROWTYPE.
B (DROP): Like CREATE, the DROP statement is DDL and is used to remove schema-level objects. It does not involve rows of data and therefore has no relevance to %ROWTYPE.
E (DELETE): Although DELETE removes records, you typically don’t need to populate or reference an entire row when deleting. The operation is usually based on conditions like WHERE id = 10. %ROWTYPE might occasionally be used in conjunction with a RETURNING clause, but it is not a primary use case for this attribute.
F (ALTER): ALTER is another DDL operation used to modify the structure of schema objects like tables or procedures. It has no relationship with row-level data or variables, making %ROWTYPE irrelevant in this context.

In summary, %ROWTYPE is most beneficial when working with row-level DML operations—particularly SELECT, UPDATE, and INSERT—where managing full rows of data improves code clarity and efficiency. Therefore, the correct answers are C, D, and G.

Question 4

Which of the following statements best explains how the EXIT and CONTINUE control statements behave in PL/SQL loops?

A. Both statements are valid in any kind of loop construct.
B. These statements always require a WHEN clause.
C. Both produce the same result by terminating loop execution.
D. These statements can only be used in labeled loops.

Correct Answer: A

Explanation:
In PL/SQL, both the EXIT and CONTINUE statements are used for controlling the flow of loop execution, but they serve different purposes. Understanding their differences and usage in various loop constructs is essential to writing clear and correct PL/SQL code.

Let’s first define the behavior of each:

EXIT: This statement immediately terminates the loop. When executed, control passes to the first statement after the loop. It can be used with or without a WHEN condition.
CONTINUE: This statement causes the loop to skip the remaining statements in the current iteration and begin the next iteration of the loop. It is typically used when a certain condition is met, allowing the loop to bypass unnecessary operations for some iterations.

Now, let’s analyze each option:

A (Both statements are valid in any kind of loop construct): This is correct. Both EXIT and CONTINUE can be used in basic LOOP, WHILE LOOP, and FOR LOOP constructs. They are fully supported and valid within these loop types. Therefore, A is the correct answer.
B (These statements always require a WHEN clause): This is incorrect. The WHEN clause is optional for both EXIT and CONTINUE. You can simply write EXIT; to break unconditionally or use EXIT WHEN condition; to exit based on a specific rule. Likewise, CONTINUE does not require a WHEN clause, though using CONTINUE WHEN condition; is common for conditional skipping.
C (Both produce the same result by terminating loop execution): This is false. While EXIT terminates the loop entirely, CONTINUE merely skips the current iteration and continues with the next one. They serve distinct purposes in loop control.
D (These statements can only be used in labeled loops): This is incorrect. PL/SQL supports both labeled and unlabeled loops, but EXIT and CONTINUE can be used without labels. Labels are useful when dealing with nested loops, where you may want to exit or continue a specific loop, but they are not a requirement.

In conclusion, EXIT and CONTINUE are flexible control mechanisms usable in all PL/SQL loop constructs, and they do not require labels or WHEN clauses. They serve different roles: one for terminating a loop, and the other for skipping to the next iteration. The correct answer is A.

Question 5

Which of the following accurately describes a key feature of user-defined records in PL/SQL?

A. A function in PL/SQL can return a user-defined record as its return type.
B. Every field in a user-defined record must exactly match a column type from a table.
C. A user-defined record must have the same number of fields as columns in a referenced table.
D. Field names in a user-defined record must exactly mirror the column names in the related table.

Correct Answer: A

Explanation:
User-defined records in PL/SQL allow you to group multiple values of different data types into a single, composite data structure. Here’s a breakdown of the options:

A. A function in PL/SQL can return a user-defined record as its return type.
This is correct. PL/SQL functions can indeed return a user-defined record as their return type. A user-defined record can have multiple fields, and the function can return the record type to the caller.
B. Every field in a user-defined record must exactly match a column type from a table.
This is incorrect. Fields in a user-defined record do not have to match the column types of a table. You can define the fields with any data type as long as they match the intended structure. The field types are independent of table columns.
C. A user-defined record must have the same number of fields as columns in a referenced table.
This is incorrect. There is no requirement that a user-defined record has the same number of fields as columns in a referenced table. While you could define a record that mirrors a table structure, it's not a restriction in PL/SQL.
D. Field names in a user-defined record must exactly mirror the column names in the related table.
This is incorrect. The field names in a user-defined record do not need to match the column names in a table. You can choose any field names as long as they are valid for PL/SQL.

Thus, the correct answer is A because a function can return a user-defined record as its return type, which is a valid and useful feature in PL/SQL.

Question 6

Which of the following is true about a package in PL/SQL?

A. A package contains only the procedure and function definitions.
B. A package can only contain variables.
C. A package contains a specification and a body.
D. A package can only be used for anonymous PL/SQL blocks.

Correct Answer: C

Explanation:
In PL/SQL, a package is a collection of related procedures, functions, variables, constants, cursors, and exceptions. It has two main components: the specification and the body. Let’s examine each option:

A. A package contains only the procedure and function definitions.
This is incorrect. A package does not only contain procedure and function definitions; it can also include variables, constants, cursors, and other components.
B. A package can only contain variables.
This is incorrect. A package can contain far more than just variables, including procedures, functions, and other elements. The package is a modular structure that groups related components.
C. A package contains a specification and a body.
This is correct. A package specification defines the interface to the package (including the procedures, functions, types, and variables that are accessible from outside the package), while the package body contains the implementation of these procedures, functions, and other components. The specification is like a header, and the body is where the logic is implemented.
D. A package can only be used for anonymous PL/SQL blocks.
This is incorrect. A package is used to organize and modularize PL/SQL code, and it can be used in stored procedures, functions, triggers, and even in anonymous PL/SQL blocks. It is not restricted to anonymous blocks.

Thus, the correct answer is C, as it accurately describes the structure of a PL/SQL package: it contains both a specification (interface) and a body (implementation).

Question 7

In PL/SQL, what is the purpose of an exception handler?

A. To define a block of code that will be executed after the PL/SQL block
B. To handle errors and exceptions that occur during the execution of a block
C. To define variables within a PL/SQL block
D. To automatically commit transactions after each SQL statement

Correct Answer: B

Explanation:
In PL/SQL, an exception handler is a critical part of the language's error-handling framework. It is used to gracefully handle runtime errors—also known as exceptions—that occur during the execution of a PL/SQL block. Rather than allowing the error to crash or terminate the process, an exception handler allows developers to respond appropriately, such as by logging the error, taking corrective action, or displaying a user-friendly message.

PL/SQL blocks are structured with three optional sections:

DECLARE – for declaring variables and types
BEGIN – for writing the executable code
EXCEPTION – for handling errors or exceptions
END – to complete the block

When an exception occurs in the BEGIN section, control immediately transfers to the EXCEPTION section if it is defined. If no handler is provided, the exception propagates up the call stack.

Let’s review the other options:

A (To define a block of code that will be executed after the PL/SQL block): This is incorrect. Exception handlers do not execute “after” a block—they execute instead of the remaining code when an error occurs.
C (To define variables within a PL/SQL block): Variable declarations are made in the DECLARE section, not in the EXCEPTION section.
D (To automatically commit transactions after each SQL statement): PL/SQL does not automatically commit after every SQL statement. Committing must be explicitly handled using the COMMIT command.

Therefore, the correct and complete purpose of an exception handler is to intercept and process errors that arise during block execution, making B the correct choice.

Question 8

What is the main difference between a function and a procedure in PL/SQL?

A. A function must always return a value, while a procedure does not need to return any value
B. A function can accept parameters, but a procedure cannot
C. A function is stored in a database table, whereas a procedure is not
D. There is no difference between a function and a procedure

Correct Answer: A

Explanation:
The primary and most fundamental difference between a function and a procedure in PL/SQL lies in the requirement for return values. A function must return a value, and this is part of its definition. A procedure, on the other hand, may perform actions (e.g., updates, inserts, calculations) and does not have to return a value—though it can return data via OUT parameters.

Here’s a breakdown of both constructs:

A function:

Must return a single value using the RETURN statement.
Can be used in SQL expressions, such as in SELECT statements, because it returns a result.
Has a defined return type in its header.

A procedure:

Is designed to perform one or more actions.
May or may not return values.
Cannot be used directly inside SQL statements (with some exceptions for autonomous procedures).

Now let’s examine why the other options are incorrect:

B (A function can accept parameters, but a procedure cannot): This is false. Both functions and procedures can accept IN, OUT, and IN OUT parameters. Procedures often use OUT parameters to return multiple values.
C (A function is stored in a database table, whereas a procedure is not): This is incorrect. Both functions and procedures are stored objects within the database schema but not in database tables. They are stored in the data dictionary as PL/SQL subprograms.
D (There is no difference between a function and a procedure): This is clearly false. The mandatory return of a value by a function is a significant and defining difference.

In summary, the correct answer is A: A function must always return a value, while a procedure does not necessarily return any value.

Question 9

Which of the following statements is true about triggers in Oracle?

A. A trigger can only be created on a single table
B. Triggers are always executed before the triggering statement
C. A trigger can be used to automatically update one table when another table is modified
D. A trigger cannot reference the :OLD and :NEW values

Correct Answer: C

Explanation:
Triggers in Oracle are used to automatically execute a set of actions when certain events occur on a table or view. Here's a breakdown of the options:

A. A trigger can only be created on a single table
This is incorrect. While triggers are often associated with a single table, they can also be created on views or other schema objects. Additionally, AFTER triggers or INSTEAD OF triggers can work on views and more than one table in some cases, depending on the logic
B. Triggers are always executed before the triggering statement
This is incorrect. Triggers can be defined to execute BEFORE or AFTER the triggering event (such as an INSERT, UPDATE, or DELETE) depending on how the trigger is created. It’s not always before. For example, an AFTER INSERT trigger is executed after the data has been inserted.
C. A trigger can be used to automatically update one table when another table is modified
This is correct. This is one of the key use cases for triggers. A trigger can be set to automatically update a different table when an insert, update, or delete operation is performed on the triggering table. For example, an AFTER INSERT trigger can update a summary table or audit table after a new row is inserted into another table.
D. A trigger cannot reference the :OLD and :NEW values
This is incorrect. The :OLD and :NEW values are used in ROW-level triggers to access the data before and after the triggering operation. For example, in an AFTER UPDATE trigger, :OLD refers to the old value before the update, and :NEW refers to the updated value. These are essential parts of triggers for tracking changes in the database.

Thus, the correct answer is C, because triggers are commonly used to automatically perform actions on related tables when certain operations are done on the triggering table.

Question 10

In PL/SQL, which of the following is a correct method for handling user-defined exceptions?

A. Use the EXCEPTION keyword after the BEGIN block to declare exceptions
B. Define exceptions using PRAGMA EXCEPTION_INIT
C. Use the RAISE statement to handle exceptions within the block
D. All of the above

Correct Answer: D

Explanation:
In PL/SQL, user-defined exceptions are a way of handling errors that are specific to your application logic. Here’s a breakdown of the options:

A. Use the EXCEPTION keyword after the BEGIN block to declare exceptions
This is incorrect. The EXCEPTION keyword is not used to declare exceptions. It is used to catch and handle exceptions that occur during the execution of a PL/SQL block. The declaration of exceptions is done in the DECLARE section of the block, not after the BEGIN.
B. Define exceptions using PRAGMA EXCEPTION_INIT
This is correct. PRAGMA EXCEPTION_INIT is used to associate an exception name with a specific Oracle error number. This allows you to handle Oracle-specific errors as user-defined exceptions. For example, you can define a custom exception for the error code -20001 using PRAGMA EXCEPTION_INIT.
C. Use the RAISE statement to handle exceptions within the block
This is correct. The RAISE statement is used to raise an exception explicitly, either a user-defined exception or a predefined exception. This can be done within the EXCEPTION section of a PL/SQL block to manage how errors are handled.
D. All of the above
This is correct. All of the methods mentioned above are part of handling user-defined exceptions in PL/SQL. You can declare exceptions, associate them with specific error codes using PRAGMA EXCEPTION_INIT, and raise them using the RAISE statement when necessary.

Thus, the correct answer is D, because all of the options listed are valid ways to handle user-defined exceptions in PL/SQL.