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Microsoft 70-762 Exam Microsoft Developing SQL Databases Exam

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Version: 17.0 Question: 1 DRAG DROP Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database named Sales that contains the following database tables: Customer, Order, and Products. The Products table and the Order table are shown in the following diagram.

The customer table includes a column that stores the data for the last order that the customer placed.

You plan to create a table named Leads. The Leads table is expected to contain approximately 20,000 records. Storage requirements for the Leads table must be minimized.

Changes to the price of any product must be less a 25 percent increase from the current price. The shipping department must be notified about order and shipping details when an order is entered into the database.

You need to implement the appropriate table objects.

Which object should you use for each table? To answer, drag the appropriate objects to the correct tables. Each object may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.

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Answer:

Explanation: The Products table needs a primary key constraint on the ProductID field.

The Orders table needs a foreign key constraint on the ProductID field, with a reference to the ProductID field in the Products table.

Question: 2 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database named Sales that contains the following database tables: Customer, Order, and Products. The Products table and the Order table are shown in the following diagram.

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The customer table includes a column that stores the data for the last order that the customer placed.

You plan to create a table named Leads. The Leads table is expected to contain approximately 20,000 records. Storage requirements for the Leads table must be minimized.

You need to implement a stored procedure that deletes a discontinued product from the Products table. You identify the following requirements: * If an open order includes a discontinued product, the records for the product must not be deleted. * The stored procedure must return a custom error message if a product record cannot be deleted.

The message must identify the OrderID for the open order.

What should you do? To answer, select the appropriate Transact-SQL segments in the answer area.

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Answer:

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Explanation: Using TRY...CATCH in Transact-SQL Errors in Transact-SQL code can be processed by using a TRY‌CATCH construct.

TRY‌CATCH can use the following error function to capture error information: ERROR_MESSAGE() returns the complete text of the error message. The text includes the values supplied for any substitutable parameters such as lengths, object names, or times.

References: https://technet.microsoft.com/en-us/library/ms179296(v=sql.105).aspx

Question: 3 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database named Sales that contains the following database tables: Customer, Order, and Products. The Products table and the Order table are shown in the following diagram.

The customer table includes a column that stores the data for the last order that the customer placed.

You plan to create a table named Leads. The Leads table is expected to contain approximately 20,000 records. Storage requirements for the Leads table must be minimized.

You need to create triggers that meet the following requirements: * Optimize the performance and data integrity of the tables. * Provide a custom error if a user attempts to create an order for a customer that does not exist. * In the Customers table, update the value for the last order placed. * Complete all actions as part of the original transaction.

In the table below, identify the trigger types that meet the requirements.

NOTE: Make only selection in each column. Each correct selection is worth one point.

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Answer:

Explanation: INSTEAD OF INSERT triggers can be defined on a view or table to replace the standard action of the INSERT statement.

AFTER specifies that the DML trigger is fired only when all operations specified in the triggering SQL statement have executed successfully.

References: https://technet.microsoft.com/en-us/library/ms175089(v=sql.105).aspx

Question: 4 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database named Sales that contains the following database tables: Customer, Order, and Products. The Products table and the Order table are shown in the following diagram.

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The customer table includes a column that stores the data for the last order that the customer placed.

You plan to create a table named Leads. The Leads table is expected to contain approximately 20,000 records. Storage requirements for the Leads table must be minimized.

The Leads table must include the columns described in the following table.

The data types chosen must consume the least amount of storage possible.

You need to select the appropriate data types for the Leads table.

In the table below, identify the data type that must be used for each table column.

NOTE: Make only one selection in each column.

Answer:

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Explanation: Bit is a Transact-SQL integer data type that can take a value of 1, 0, or NULL. Smallint is aT ransact-SQL integer data type that can take a value in the range from -32,768 to 32,767. int, bigint, smallint, and tinyint (Transact-SQL) Exact-number data types that use integer data.

References: https://msdn.microsoft.com/en-us/library/ms187745.aspx https://msdn.microsoft.com/en-us/library/ms177603.aspx

Question: 5 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database named Sales that contains the following database tables: Customer, Order, and Products. The Products table and the Order table are shown in the following diagram.

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The customer table includes a column that stores the data for the last order that the customer placed.

You plan to create a table named Leads. The Leads table is expected to contain approximately 20,000 records. Storage requirements for the Leads table must be minimized.

You need to modify the database design to meet the following requirements: * Rows in the Orders table must always have a valid value for the ProductID column. * Rows in the Products table must not be deleted if they are part of any rows in the Orders table. * All rows in both tables must be unique.

In the table below, identify the constraint that must be configured for each table.

NOTE: Make only one selection in each column.

Answer:

Explanation: A FOREIGN KEY in one table points to a PRIMARY KEY in another table. Here the foreign key constraint is put on the ProductID in the Orders, and points to the ProductID of the Products table.

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With a check constraint on the ProductID we can ensure that the Products table contains only unique rows.

References: http://www.w3schools.com/sql/sql_foreignkey.asp

Question: 6 DRAG DROP Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in the series.

You have a database named Sales that contains the following database tables. Customer, Order, and Products. The Products table and the order table shown in the following diagram.

The Customer table includes a column that stores the date for the last order that the customer placed.

You plan to create a table named Leads. The Leads table is expected to contain approximately 20,000 records. Storage requirements for the Leads table must be minimized.

You need to begin to modify the table design to adhere to third normal form.

Which column should you remove for each table? To answer? drag the appropriate column names to the correct locations. Each column name may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.

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Answer:

Explanation: In the Products table the SupplierName is dependent on the SupplierID, not on the ProductID. In the Orders table the ProductName is dependent on the ProductID, not on the OrderID. Note: A table is in third normal form when the following conditions are met: * It is in second normal form. * All non-primary fields are dependent on the primary key.

Second normal form states that it should meet all the rules for First 1Normnal Form and there must be no partial dependencies of any of the columns on the primary key.

First normal form (1NF) sets the very basic rules for an organized database: * Define the data items required, because they become the columns in a table. Place related data items in a table. * Ensure that there are no repeating groups of data. * Ensure that there is a primary key.

References: https://www.tutorialspoint.com/sql/third-normal-form.htm

Question: 7 Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database that contains the following tables: BlogCategory, BlogEntry, ProductReview, Product, and SalesPerson. The tables were created using the following Transact SQL statements:

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You must modify the ProductReview Table to meet the following requirements: * The table must reference the ProductID column in the Product table * Existing records in the ProductReview table must not be validated with the Product table. * Deleting records in the Product table must not be allowed if records are referenced by the ProductReview table. * Changes to records in the Product table must propagate to the ProductReview table.

You also have the following database tables: Order, ProductTypes, and SalesHistory, The transact-SQL statements for these tables are not available.

You must modify the Orders table to meet the following requirements: * Create new rows in the table without granting INSERT permissions to the table. * Notify the sales person who places an order whether or not the order was completed.

You must add the following constraints to the SalesHistory table: * a constraint on the SaleID column that allows the field to be used as a record identifier * a constant that uses the ProductID column to reference the Product column of the ProductTypes table * a constraint on the CategoryID column that allows one row with a null value in the column * a constraint that limits the SalePrice column to values greater than four Finance department users must be able to retrieve data from the SalesHistory table for sales persons where the value of the SalesYTD column is above a certain threshold.

You plan to create a memory-optimized table named SalesOrder. The table must meet the following requirements: * The table must hold 10 million unique sales orders. * The table must use checkpoints to minimize I/O operations and must not use transaction logging. * Data loss is acceptable.

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Performance for queries against the SalesOrder table that use Where clauses with exact equality operations must be optimized.

You need to enable referential integrity for the ProductReview table.

How should you complete the relevant Transact-SQL statement? To answer? select the appropriate Transact-SQL segments in the answer area.

Select two alternatives.

A. For the first selection select: WITH CHECK B. For the first selection select: WITH NOCHECK C. For the second selection select: ON DELETE NO ACTION ON UPDATE CASCADE D. For the second selection select: ON DELETE CASCADE ON UPDATE CASCADE E. For the second selection select: ON DELETE NO ACTION ON UPDATE NO ACTION F. For the second selection select: ON DELETE CASCADE ON UPDATE NO ACTION

Answer: B,C Explanation: B: We should use WITH NOCHECK as existing records in the ProductReview table must not be validated with the Product table.

C: Deletes should not be allowed, so we use ON DELETE NO ACTION. Updates should be allowed, so we use ON DELETE NO CASCADE NO ACTION: the Database Engine raises an error, and the update action on the row in the parent table is rolled back.

CASCADE: corresponding rows are updated in the referencing table when that row is updated in the parent table.

Note: ON DELETE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } Specifies what action happens to rows in the table that is altered, if those rows have a referential relationship and the referenced row is deleted from the parent table. The default is NO ACTION. ON UPDATE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } Specifies what action happens to rows in the table altered when those rows have a referential relationship and the referenced row is updated in the parent table. The default is NO ACTION. Note: You must modify the ProductReview Table to meet the following requirements: 1. The table must reference the ProductID column in the Product table 2. Existing records in the ProductReview table must not be validated with the Product table.

3. Deleting records in the Product table must not be allowed if records are referenced by the ProductReview table.

4. Changes to records in the Product table must propagate to the ProductReview table.

References: https://msdn.microsoft.com/en-us/library/ms190273.aspx https://msdn.microsoft.com/en-us/library/ms188066.aspx

Question: 8 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database that contains the following tables: BlogCategory, BlogEntry, ProductReview, Product, and SalesPerson. The tables were created using the following Transact SQL statements:

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You must modify the ProductReview Table to meet the following requirements: * The table must reference the ProductID column in the Product table * Existing records in the ProductReview table must not be validated with the Product table. * Deleting records in the Product table must not be allowed if records are referenced by the ProductReview table. * Changes to records in the Product table must propagate to the ProductReview table.

You also have the following database tables: Order, ProductTypes, and SalesHistory, The transact-SQL statements for these tables are not available.

You must modify the Orders table to meet the following requirements: * Create new rows in the table without granting INSERT permissions to the table. * Notify the sales person who places an order whether or not the order was completed.

You must add the following constraints to the SalesHistory table: * a constraint on the SaleID column that allows the field to be used as a record identifier * a constant that uses the ProductID column to reference the Product column of the ProductTypes table * a constraint on the CategoryID column that allows one row with a null value in the column * a constraint that limits the SalePrice column to values greater than four Finance department users must be able to retrieve data from the SalesHistory table for sales persons where the value of the SalesYTD column is above a certain threshold.

You plan to create a memory-optimized table named SalesOrder. The table must meet the following

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requirements: * The table must hold 10 million unique sales orders. * The table must use checkpoints to minimize I/O operations and must not use transaction logging. * Data loss is acceptable.

Performance for queries against the SalesOrder table that use Where clauses with exact equality operations must be optimized.

How should you complete the Transact-SQL statements? To answer, select the appropriate TransactSQL segments in the answer area.

Answer:

Explanation: From question: Finance department users must be able to retrieve data from the SalesHistory table for sales persons where the value of the SalesYTD column is above a certain threshold.

CREATE VIEW (Transact-SQL) creates a virtual table whose contents (columns and rows) are defined by a query. Use this statement to create a view of the data in one or more tables in the database.

SCHEMABINDING binds the view to the schema of the underlying table or tables. When SCHEMABINDING is specified, the base table or tables cannot be modified in a way that would affect

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the view definition.

References: https://msdn.microsoft.com/en-us/library/ms187956.aspx

Question: 9 Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database that contains the following tables: BlogCategory, BlogEntry, ProductReview, Product, and SalesPerson. The tables were created using the following Transact SQL statements:

You must modify the ProductReview Table to meet the following requirements: * The table must reference the ProductID column in the Product table * Existing records in the ProductReview table must not be validated with the Product table. * Deleting records in the Product table must not be allowed if records are referenced by the ProductReview table. * Changes to records in the Product table must propagate to the ProductReview table.

You also have the following database tables: Order, ProductTypes, and SalesHistory, The transact-SQL statements for these tables are not available.

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You must modify the Orders table to meet the following requirements: * Create new rows in the table without granting INSERT permissions to the table. * Notify the sales person who places an order whether or not the order was completed.

You must add the following constraints to the SalesHistory table: * a constraint on the SaleID column that allows the field to be used as a record identifier * a constant that uses the ProductID column to reference the Product column of the ProductTypes table * a constraint on the CategoryID column that allows one row with a null value in the column * a constraint that limits the SalePrice column to values greater than four Finance department users must be able to retrieve data from the SalesHistory table for sales persons where the value of the SalesYTD column is above a certain threshold.

You plan to create a memory-optimized table named SalesOrder. The table must meet the following requirements: * The table must hold 10 million unique sales orders. * The table must use checkpoints to minimize I/O operations and must not use transaction logging. * Data loss is acceptable.

Performance for queries against the SalesOrder table that use Where clauses with exact equality operations must be optimized.

You need to modify the design of the Orders table.

What should you create?

A. a stored procedure with the RETURN statement B. a FOR UPDATE trigger C. an AFTER UPDATE trigger D. a user defined function

Answer: D Explanation: Requirements: You must modify the Orders table to meet the following requirements: 1. Create new rows in the table without granting INSERT permissions to the table.

2. Notify the sales person who places an order whether or not the order was completed.

References: https://msdn.microsoft.com/en-us/library/ms186755.aspx

Question: 10 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database that contains the following tables: BlogCategory, BlogEntry, ProductReview, Product, and SalesPerson. The tables were created using the following Transact SQL statements:

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You must modify the ProductReview Table to meet the following requirements: * The table must reference the ProductID column in the Product table * Existing records in the ProductReview table must not be validated with the Product table. * Deleting records in the Product table must not be allowed if records are referenced by the ProductReview table. * Changes to records in the Product table must propagate to the ProductReview table.

You also have the following database tables: Order, ProductTypes, and SalesHistory, The transact-SQL statements for these tables are not available.

You must modify the Orders table to meet the following requirements: * Create new rows in the table without granting INSERT permissions to the table. * Notify the sales person who places an order whether or not the order was completed.

You must add the following constraints to the SalesHistory table: * a constraint on the SaleID column that allows the field to be used as a record identifier * a constant that uses the ProductID column to reference the Product column of the ProductTypes table * a constraint on the CategoryID column that allows one row with a null value in the column * a constraint that limits the SalePrice column to values greater than four Finance department users must be able to retrieve data from the SalesHistory table for sales persons where the value of the SalesYTD column is above a certain threshold.

You plan to create a memory-optimized table named SalesOrder. The table must meet the following requirements: * The table must hold 10 million unique sales orders. * The table must use checkpoints to minimize I/O operations and must not use transaction logging. * Data loss is acceptable.

Performance for queries against the SalesOrder table that use Where clauses with exact equality

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operations must be optimized.

You need to update the SalesHistory table How should you complete the Transact_SQL statement? To answer? select the appropriate TransactSQL, segments in the answer area.

Answer:

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Explanation: Box 1: SaleID must be the primary key, as a constraint on the SaleID column that allows the field to be used as a record identifier is required.

Box2: A constraint that limits the SalePrice column to values greater than four.

Box 3: UNIQUE A constraint on the CategoryID column that allows one row with a null value in the column.

Box 4: A foreign key constraint must be put on the productID referencing the ProductTypes table, as a constraint that uses the ProductID column to reference the Product column of the ProductTypes table is required.

Note: Requirements are: You must add the following constraints to the SalesHistory table:

Question: 11 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database that contains the following tables: BlogCategory, BlogEntry, ProductReview, Product, and SalesPerson. The tables were created using the following Transact SQL statements:

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You must modify the ProductReview Table to meet the following requirements: * The table must reference the ProductID column in the Product table * Existing records in the ProductReview table must not be validated with the Product table. * Deleting records in the Product table must not be allowed if records are referenced by the ProductReview table. * Changes to records in the Product table must propagate to the ProductReview table.

You also have the following database tables: Order, ProductTypes, and SalesHistory, The transact-SQL statements for these tables are not available.

You must modify the Orders table to meet the following requirements: * Create new rows in the table without granting INSERT permissions to the table. * Notify the sales person who places an order whether or not the order was completed.

You must add the following constraints to the SalesHistory table: * a constraint on the SaleID column that allows the field to be used as a record identifier * a constant that uses the ProductID column to reference the Product column of the ProductTypes table * a constraint on the CategoryID column that allows one row with a null value in the column * a constraint that limits the SalePrice column to values greater than four Finance department users must be able to retrieve data from the SalesHistory table for sales persons where the value of the SalesYTD column is above a certain threshold.

You plan to create a memory-optimized table named SalesOrder. The table must meet the following requirements: * The table must hold 10 million unique sales orders. * The table must use checkpoints to minimize I/O operations and must not use transaction logging. * Data loss is acceptable.

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Performance for queries against the SalesOrder table that use Where clauses with exact equality operations must be optimized.

You need to create the Sales Order table How should you complete the table definition? To answer? select the appropriate Transact-SQL segments in the answer area.

Answer:

Explanation: Box 1: NONCLUSTERED HASHWITH (BUCKET_COUNT = 10000000) Hash index is preferable over a nonclustered index when queries test the indexed columns by use of a WHERE clause with an exact equality on all index key columns. We should use a bucket count of 10 million.

Box 2: SCHEMA_ONLY Durability: The value of SCHEMA_AND_DATA indicates that the table is durable, meaning that changes are persisted on disk and survive restart or failover. SCHEMA_AND_DATA is the default value.

The value of SCHEMA_ONLY indicates that the table is non-durable. The table schema is persisted but any data updates are not persisted upon a restart or failover of the database.

DURABILITY=SCHEMA_ONLY is only allowed with MEMORY_OPTIMIZED=ON. References: https://msdn.microsoft.com/en-us/library/mt670614.aspx

Question: 12 HOTSPOT Note: This question is part of a series of questions that use the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.

You have a database that contains the following tables: BlogCategory, BlogEntry, ProductReview, Product, and SalesPerson. The tables were created using the following Transact SQL statements:

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You must modify the ProductReview Table to meet the following requirements: * The table must reference the ProductID column in the Product table * Existing records in the ProductReview table must not be validated with the Product table. * Deleting records in the Product table must not be allowed if records are referenced by the ProductReview table. * Changes to records in the Product table must propagate to the ProductReview table.

You also have the following database tables: Order, ProductTypes, and SalesHistory, The transact-SQL statements for these tables are not available.

You must modify the Orders table to meet the following requirements: * Create new rows in the table without granting INSERT permissions to the table. * Notify the sales person who places an order whether or not the order was completed.

You must add the following constraints to the SalesHistory table: * a constraint on the SaleID column that allows the field to be used as a record identifier * a constant that uses the ProductID column to reference the Product column of the ProductTypes table * a constraint on the CategoryID column that allows one row with a null value in the column * a constraint that limits the SalePrice column to values greater than four Finance department users must be able to retrieve data from the SalesHistory table for sales persons where the value of the SalesYTD column is above a certain threshold.

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You plan to create a memory-optimized table named SalesOrder. The table must meet the following requirements: * The table must hold 10 million unique sales orders. * The table must use checkpoints to minimize I/O operations and must not use transaction logging. * Data loss is acceptable.

Performance for queries against the SalesOrder table that use Where clauses with exact equality operations must be optimized.

You need to create a stored procedure named spDeleteCategory to delete records in the database.

The stored procedure must meet the following requirements: * Delete records in both the BlogEntry and BlogCategory tables where CategoryId equals parameter @CategoryId. * Avoid locking the entire table when deleting records from the BlogCategory table. * If an error occurs during a delete operation on either table, all changes must be rolled back, otherwise all changes should be committed.

How should you complete the procedure? To answer, select the appropriate Transact-SQL segments in the answer area.

Answer:

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Explanation: Box 1: SET TRANSACTION ISOLATION LEVEL READ COMMITTED You can minimize locking contention while protecting transactions from dirty reads of uncommitted data modifications by using either of the following: * The READ COMMITTED isolation level with the READ_COMMITTED_SNAPSHOT database option set ON. * The SNAPSHOT isolation level.

With ROWLOCK we should use READ COMMITTED Box 2: ROWLOCK Requirement: Avoid locking the entire table when deleting records from the BlogCategory table ROWLOCK specifies that row locks are taken when page or table locks are ordinarily taken. When specified in transactions operating at the SNAPSHOT isolation level, row locks are not taken unless ROWLOCK is combined with other table hints that require locks, such as UPDLOCK and HOLDLOCK. Box 3: COMMIT Box 4: ROLLBACK

Question: 13 DRAG DROP You are analyzing the performance of a database environment.

Applications that access the database are experiencing locks that are held for a large amount of time.

You are experiencing isolation phenomena such as dirty, nonrepeatable and phantom reads.

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You need to identify the impact of specific transaction isolation levels on the concurrency and consistency of data.

What are the consistency and concurrency implications of each transaction isolation level? To answer, drag the appropriate isolation levels to the correct locations. Each isolation level may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.

Answer:

Explanation: Read Uncommitted (aka dirty read): A transaction T1executing under this isolation level can access data changed by concurrent transaction(s).

Pros:No read locks needed to read data (i.e. no reader/writer blocking). Note, T1 still takes transaction duration locks for any data modified.

Cons: Data is not guaranteed to be transactionally consistent.

Read Committed: A transaction T1 executing under this isolation level can only access committed data.

Pros: Good compromise between concurrency and consistency.

Cons: Locking and blocking. The data can change when accessed multiple times within the same

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transaction.

Repeatable Read: A transaction T1 executing under this isolation level can only access committed data with an additional guarantee that any data read cannot change (i.e. it is repeatable) for the duration of the transaction.

Pros: Higher data consistency.

Cons: Locking and blocking. The S locks are held for the duration of the transaction that can lower the concurrency. It does not protect against phantom rows.

Serializable: A transaction T1 executing under this isolation level provides the highest data consistency including elimination of phantoms but at the cost of reduced concurrency. It prevents phantoms by taking a range lock or table level lock if range lock can’t be acquired (i.e. no index on the predicate column) for the duration of the transaction.

Pros: Full data consistency including phantom protection.

Cons: Locking and blocking. The S locks are held for the duration of the transaction that can lower the concurrency.

References: https://blogs.msdn.microsoft.com/sqlcat/2011/02/20/concurrency-series-basics-oftransaction-isolation-levels/

Question: 14 DRAG DROP You are evaluating the performance of a database environment.

You must avoid unnecessary locks and ensure that lost updates do not occur.

You need to choose the transaction isolation level for each data scenario.

Which isolation level should you use for each scenario? To answer, drag the appropriate isolation levels to the correct scenarios. Each isolation may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.

Answer:

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Explanation: Box 1: Readcommitted Read Committed: A transaction T1 executing under this isolation level can only access committed data.

Pros: Good compromise between concurrency and consistency.

Cons: Locking and blocking. The data can change when accessed multiple times within the same transaction.

Box 2: Read Uncommitted Read Uncommitted (aka dirty read): A transaction T1 executing under this isolation level can access data changed by concurrent transaction(s).

Pros: No read locks needed to read data (i.e. no reader/writer blocking). Note, T1 still takes transaction duration locks for any data modified.

Cons: Data is not guaranteed to be transactionally consistent.

Box 3: Serializable Serializable: A transaction T1 executing under this isolation level provides the highest data consistency including elimination of phantoms but at the cost of reduced concurrency. It prevents phantoms by taking a range lock or table level lock if range lock can’t be acquired (i.e. no index on the predicate column) for the duration of the transaction.

Pros: Full data consistency including phantom protection.

Cons: Locking and blocking. The S locks are held for the duration of the transaction that can lower the concurrency.

References: https://blogs.msdn.microsoft.com/sqlcat/2011/02/20/concurrency-series-basics-oftransaction-isolation-levels/

Question: 15 DRAG DROP You have two database tables. Table1 is a partitioned table and Table 2 is a non-partitioned table.

Users report that queries take a long time to complete. You monitor queries by using Microsoft SQL Server Profiler. You observe lock escalation for Table1 and Table 2.

You need to allow escalation of Table1 locks to the partition level and prevent all lock escalation for Table2.

Which Transact-SQL statement should you run for each table? To answer, drag the appropriate Transact-SQL statements to the correct tables. Each command may be used once, more than once, or

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Answer:

Explanation: Since SQL Server 2008 you can also control how SQL Server performs the Lock Escalation – through the ALTER TABLE statement and the property LOCK_ESCALATION. There are 3 different options available: Box 1: Table1, Auto The default option is TABLE, means that SQL Server *always* performs the Lock Escalation to the table level –even when the table is partitioned. If you have your table partitioned, and you want to have a Partition Level Lock Escalation (because you have tested your data access pattern, and you don’t cause deadlocks with it), then you can change the option to AUTO. AUTO means that the Lock Escalation is performed to the partition level, if the table is partitioned, and otherwise to the table level.

Box 2: Table 2, DISABLE With the option DISABLE you can completely disable the Lock Escalation for that specific table.

For partitioned tables, use the LOCK_ESCALATION option of ALTER TABLE to escalate locks to the HoBT level instead of the table or to disable lock escalation.

References: http://www.sqlpassion.at/archive/2014/02/25/lock-escalations/

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