Reference Guide > Function Support for Data Sources > Function Support Issues when Combining Data Sources
 
Function Support Issues when Combining Data Sources
Data virtualization typically involves many data sources, each with its own collection of data types and functions and its own way of handling them. Besides this, queries and functions can be executed natively in the TDV Server. The number of combinations, therefore, is very large.
Several issues that might result from combining data sources are covered:
• ASCII Function with Empty String Argument
• Case Sensitivity and Trailing Spaces
• Collating Sequence
• Data Precision
• Decimal Digit Limitation on Functions
• INSTR Function
• Interval Calculations
• Mapping of Native to TDV Data Types Across TDV Versions
• MERGE
• ORDER BY Clause
• SPACE Function
• SQL Server Sorting Order
• Time Functions
• Truncation vs. Rounding