The SQL statement used to create a user-defined function in DB2 is "CREATE FUNCTION". This statement allows developers to define custom functions tailored to specific requirements. 

DB2 primarily uses a hash key for data distribution in partitioning. This involves hashing the data using a hash function and distributing it across partitions based on the result of the hash function. 

DB2 provides built-in functions specifically designed for querying and manipulating semi-structured data types such as XML and JSON. These functions enable developers to perform various operations on semi-structured data stored in DB2 databases, such as extracting values, navigating hierarchical structures, and transforming data formats. 

The primary objective of normalization in DB2 is to minimize redundancy by organizing data efficiently. Reducing redundancy helps improve data integrity, save storage space, and ensure consistency in the database. 

User-defined functions can contribute to improving performance in DB2 applications by optimizing for reusability. When functions are designed to be reused across multiple queries and applications, it reduces the need for redundant code, leading to improved code maintenance and enhanced application performance. Additionally, by encapsulating frequently used logic within functions, developers can streamline query execution and promote code modularity. 

A scrollable cursor in DB2 allows for navigating both forward and backward through the result set obtained from a query. This feature provides flexibility to applications in iterating over query results in different directions based on their requirements. 

The SQL command used to create a view in DB2 is CREATE VIEW. This command allows users to define a virtual table based on the result set of a SELECT statement. 

RESTful APIs offer a modern and flexible approach to data access. They facilitate communication between different systems over the internet, allowing clients to interact with databases through standard HTTP methods. With RESTful APIs, developers can access and manipulate data stored in DB2 databases from various platforms and programming languages, fostering interoperability and ease of integration. This approach simplifies application development by providing a uniform interface for accessing database resources, promoting agility and scalability in software development projects. 

When designing triggers in DB2, it's crucial to consider various factors to avoid performance issues. One such factor is the frequency of trigger execution. Triggers that fire frequently can impact database performance, especially if they involve complex logic or operations on large data sets. The complexity of trigger logic is another consideration. Complex triggers may require more CPU and memory resources, leading to performance degradation. Additionally, the size of the affected data set can impact trigger performance, as triggers must process all affected rows. Therefore, it's essential to carefully analyze these factors and optimize trigger design to minimize performance overhead in a DB2 environment. 

The DB2 Command Line Processor (CLP) offers batch capabilities for executing SQL commands and scripts. It allows users to run SQL commands and scripts in batch mode, enabling automation and efficient execution of tasks without the need for manual intervention.