JDBC enables Java applications to communicate with DB2 databases through ________.

  • API calls
  • Connection pooling
  • Object-relational mapping
  • SQL queries
JDBC (Java Database Connectivity) allows Java applications to communicate with DB2 databases through API calls. JDBC provides a set of interfaces and classes for executing SQL queries, managing connections, and processing results. 

In an ERD, a double-lined rectangle represents a(n) ________ entity.

  • Dependent
  • Derived
  • Strong
  • Weak
In an ERD, a double-lined rectangle represents a strong entity. A strong entity is one that exists independently of other entities and has its own unique identifier. It is not dependent on any other entity for its existence. 

The VARIANCE() function in DB2 returns the ________ of the values in a column.

  • Variance
  • Standard Deviation
  • Mean
  • Median
The correct option is 1. The VARIANCE() function in DB2 calculates the variance of the values in a column, which represents how much the values in the column deviate from the mean value of the column. 

What are the key considerations for selecting an encryption algorithm in DB2?

  • Compression ratio, backup speed, transaction throughput
  • Database schema complexity, indexing efficiency, storage overhead
  • Network latency, query optimization, user authentication
  • Strength of encryption, performance impact, compatibility with regulatory requirements
When selecting an encryption algorithm in DB2, key considerations include the strength of encryption, performance impact, and compatibility with regulatory requirements. These factors ensure data security and compliance. 

Explain the concept of transitive dependency in the context of normalization.

  • A field depends on another field which is not the primary key
  • A field depends on the primary key through another non-prime attribute
  • A non-prime attribute depends on another non-prime attribute
  • A primary key depends on a non-prime attribute
Transitive dependency occurs in a relation when a non-prime attribute depends on another non-prime attribute, which, in turn, depends on the primary key. This dependency chain indicates that the non-prime attribute is indirectly dependent on the primary key through another non-prime attribute, violating the rules of normalization. 

Scenario: A company is designing an ERD for its HR system. They identify a scenario where an employee may have multiple dependents, but a dependent can only belong to one employee. What type of relationship does this represent in the ERD?

  • Many-to-Many
  • None of the above
  • One-to-Many
  • One-to-One
This scenario illustrates a One-to-Many relationship in the ERD. It implies that one employee can have multiple dependents, but each dependent can only be associated with one employee. 

Scenario: A database designer is creating an ERD for a banking system. They encounter a scenario where a customer may have multiple accounts, but an account can only belong to one customer. What type of relationship does this represent in the ERD?

  • Many-to-Many
  • None of the above
  • One-to-Many
  • One-to-One
This scenario represents a One-to-Many relationship in the ERD. In a One-to-Many relationship, one entity instance can be associated with multiple instances of another entity, but each instance of the second entity can only be associated with one instance of the first entity. In this case, one customer can have multiple accounts, but each account can only belong to one customer. 

In DB2, what is the difference between a clustered index and a non-clustered index?

  • A clustered index is faster for read operations.
  • A clustered index physically orders the data on disk.
  • A non-clustered index does not affect the physical order of data.
  • A non-clustered index is faster for write operations.
A clustered index physically reorders the rows in the table based on the index key, which means the rows are stored on disk in the same order as the index. This speeds up retrieval of data based on that index key but may slow down inserts and updates because the rows must be physically reordered. A non-clustered index does not change the physical order of the data on disk and thus doesn't affect insert or update performance, but may be slower for retrieval operations. 

How does referential integrity ensure data integrity in DB2?

  • By compressing the data
  • By creating indexes
  • By encrypting the data
  • By enforcing relationships between tables
Referential integrity in DB2 ensures data integrity by enforcing relationships between tables. This means that when a foreign key in one table references a primary key in another table, the integrity of the relationship is maintained. For example, if a record in the parent table is deleted or updated, the corresponding records in the child table are also updated or deleted to maintain consistency. This helps prevent orphan records and ensures that the data remains accurate and consistent throughout the database. 

Which command line tool is commonly used for basic database administration tasks in DB2?

  • DB2 Command Line Processor (CLP)
  • MySQL Command Line Client
  • SQL Server Management Studio
  • SQL*Plus
The DB2 Command Line Processor (CLP) is commonly used for basic database administration tasks in DB2. It provides a command-line interface for executing SQL statements, managing database objects, and performing administrative tasks. CLP offers flexibility and efficiency for administrators to interact with the DB2 database system directly from the command line.