Tag: databases

To maintain referential integrity between two tables, the utility that should be used is the CHECK utility.

Option A) LOAD - The LOAD utility is used to load data into a table. While it is important to load data accurately, it does not specifically address maintaining referential integrity between tables.

Option B) CHECK - The CHECK utility is used to verify the integrity of the data and relationships between tables. It can be used to enforce referential integrity by checking that foreign key values in one table match the primary key values in another table.

Option C) REORG - The REORG utility is used to reorganize data within a table to improve performance. While it can help maintain the overall health of the database, it does not specifically focus on referential integrity between tables.

Option D) RUNSTATS - The RUNSTATS utility is used to collect statistics about table and index data. These statistics are used by the database optimizer to choose the most efficient access paths for queries. While it is important for query optimization, it does not specifically address referential integrity.

The correct answer is B) CHECK, as it is specifically designed to verify referential integrity and relationships between tables.

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To maintain consistency for a list of tablespaces, the utility that should be used is QUIESCE.

Option A) QUIESCE - This option is correct because the QUIESCE utility is used to temporarily disable updates to a tablespace. It ensures that no changes are made to the data during maintenance operations, thus maintaining consistency.

Option B) CHECK - This option is incorrect because the CHECK utility is used to perform integrity checks on table data, but it does not specifically maintain consistency for tablespaces.

Option C) REORG - This option is incorrect because the REORG utility is used to reorganize table data and indexes, which can improve performance and reclaim space. While it can contribute to maintaining consistency indirectly, it is not the primary utility for this purpose.

Option D) RUNSTATS - This option is incorrect because the RUNSTATS utility is used to collect statistics about the data in a table or index, which helps the database optimizer make informed decisions about query execution. It does not directly maintain consistency for tablespaces.

The correct answer is A) QUIESCE. This option is correct because the QUIESCE utility is specifically designed to maintain consistency for a list of tablespaces by temporarily disabling updates.

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To answer this question, you need to understand the purpose of each utility in DB2.

Option A) QUIESCE - This option is incorrect because the QUIESCE utility is used to temporarily halt the activity on a database or tablespace, allowing for maintenance operations to be performed. It does not restore tablespaces and indexes to a specific instance.

Option B) RECOVER - This option is correct. The RECOVER utility is used to restore and recover tablespaces and indexes in DB2. It allows you to restore data from a backup to a specific instance, ensuring data consistency and integrity.

Option C) REORG - This option is incorrect. The REORG utility is used to reorganize DB2 objects, such as tables and indexes, to improve performance and reclaim space. It does not restore tablespaces and indexes to a specific instance.

Option D) RUNSTATS - This option is incorrect. The RUNSTATS utility is used to collect statistics about DB2 objects, such as tables and indexes, to help the query optimizer make efficient execution plans. It does not restore tablespaces and indexes to a specific instance.

The correct answer is B) RECOVER. This option is correct because the RECOVER utility is specifically designed to restore and recover tablespaces and indexes in DB2.

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To create a trigger, you need all of the following options:

A. Triggering Table - This is the table on which the trigger will be created. The trigger will be executed whenever a certain event occurs on this table.

B. Triggering Event - This is the event that will trigger the execution of the trigger. Examples of triggering events include INSERT, UPDATE, or DELETE operations on the triggering table.

C. Triggered Action - This is the action that will be performed when the trigger is executed. The triggered action can be a set of SQL statements or a call to a stored procedure.

Therefore, the correct answer is D) All the above, as all of these options are necessary components for creating a trigger.

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To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) Validate input data - This option is incorrect. Triggers can be used to validate input data. Triggers can be set to execute before or after an insert, update, or delete operation and can be used to enforce data validation rules.

Option B) Automatically generate values for newly inserted rows - This option is incorrect. Triggers can be used to automatically generate values for newly inserted rows. For example, a trigger can be set to insert a default value into a specific column when a new row is inserted.

Option C) Support alerts - This option is incorrect. Triggers can be used to support alerts. For example, a trigger can be set to send an alert or notification when a specific condition is met.

Option D) To implement Referential Integrity - This option is correct. Triggers cannot be used to implement referential integrity. Referential integrity is typically enforced through foreign key constraints and not through triggers.

The correct answer is D) To implement Referential Integrity. This option is correct because triggers are not used to implement referential integrity. Referential integrity is enforced through foreign key constraints.

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To answer this question, you need to understand the concept of locks in the context of transaction management. Let's go through each option to understand why it is correct or incorrect:

Option A) If transaction A holds X lock on row R, If transaction B requests for S lock, then B would go into a wait state until A releases the lock. This option is correct because in most concurrency control protocols, if a transaction holds an exclusive (X) lock on a resource (row R in this case), other transactions requesting shared (S) locks will be put into a wait state until the exclusive lock is released. This ensures that only one transaction at a time can have exclusive access to a resource.

Option B) If transaction A holds S lock on row R, If transaction B requests for S lock, then B would be granted the lock. This option is correct because shared (S) locks are compatible with other shared locks. If a transaction holds a shared lock on a resource, other transactions requesting shared locks on the same resource can be granted the lock. This allows multiple transactions to access the resource simultaneously.

Option C) If transaction A holds X lock on row R, If transaction B requests for X lock, then B would be granted the lock. This option is incorrect because exclusive (X) locks are not compatible with other exclusive locks. If a transaction holds an exclusive lock on a resource, other transactions requesting exclusive locks on the same resource will have to wait until the lock is released.

Option D) If transaction A holds S lock on row R, If transaction B requests for X lock, then B would be granted the lock. This option is incorrect because exclusive (X) locks are not compatible with shared (S) locks. If a transaction holds a shared lock on a resource, other transactions requesting exclusive locks on the same resource will have to wait until the shared lock is released.

The correct answers are A and B. These options correctly describe the behavior of locks in a transactional system.

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To answer this question, you need to understand the concept of LOCKSIZE in the context of databases. LOCKSIZE determines the level at which locks are acquired and released during data modification operations.

Let's go through each option to understand why it is correct or incorrect:

Option A) Database - This option is incorrect because LOCKSIZE is not applicable at the database level. LOCKSIZE is set at a more granular level, such as tablespace, table, or view.

Option B) Tablespace - This option is correct because LOCKSIZE can be set at the tablespace level. By specifying the LOCKSIZE at the tablespace level, you can control how locks are acquired and released for tables within that tablespace.

Option C) Table - This option is correct because LOCKSIZE can also be set at the table level. By specifying the LOCKSIZE at the table level, you can control how locks are acquired and released for that particular table.

Option D) View - This option is incorrect because LOCKSIZE is not applicable at the view level. LOCKSIZE is typically associated with physical data structures like tablespace or table.

The correct answer is B and C. These options are correct because LOCKSIZE can be set at the tablespace and table levels to control how locks are acquired and released during data modification operations.

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