Why dynamic columns are not possible in SSIS

SSIS PowerPack Getting Started
1

Problem

You want a single Source or Destination component to handle a variable number of columns at runtime, for example, one component that adapts automatically to 3 different URLs or tables, each returning a different set of columns. This is not possible in SSIS.

Cause

Dynamic columns are not possible in SSIS by design:

  1. The SSIS Data Flow uses a fixed-column architecture to support high-performance buffer processing.
  2. Column metadata is set once, at design time; it cannot change during runtime.
  3. This applies regardless of the source type (API, file, database), since the limitation is in the SSIS Data Flow engine itself, not in any specific ZappySys component.

Solution

Use one of these approaches depending on your scenario.

Use a separate source per URL/table

If your 3 URLs or tables return different sets of columns, add 3 separate Source components (one per URL/table), each with its own fixed metadata.

Use expressions to swap the URL/table dynamically

If your 3 URLs or tables return the same number and type of columns, you can keep a single Source component and use variables or SSIS expressions to change the URL or table name dynamically at runtime, since the metadata (columns) stays identical; only the data source itself changes per run.

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Need more help?

If you’re unsure which approach fits your scenario, contact ZappySys Support: