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Multiple tag values and concatenation

Atlan supports assigning multiple tag values to a single Snowflake object. When multiple tag values are assigned, Atlan concatenates them into a single string using a configurable delimiter.

Requirements​

  • Both reverse sync and concatenation must be enabled for multi-value synchronization to work.

Constraints​

When configuring multiple tag values, keep the following constraints in mind:

  • The chosen delimiter can't appear inside any tag value to prevent parsing errors.
  • The concatenated tag values length must not exceed 256 characters.
  • If the allowed list is enabled for a tag in Snowflake, concatenated tag values that you attach to Snowflake objects must come from the tag’s predefined list. To use a new value, add it to the list.
  • Each tag supports up to 300 values. For more information, see Snowflake tag quota for objects.

How concatenation works​

Important

Tag concatenation is an Atlan feature. Concatenated values created in Atlan are synced to Snowflake. However, if you concatenate tag values in Snowflake workflows, those concatenated references won't be synced back to Atlan.

Atlan manages multiple tag values by concatenating them into a single string that can be synchronized back to Snowflake. The process involves sorting, concatenation, and synchronization behaviors described below.

Single values​

When only one value is assigned to a tag, no concatenation occurs. The single value is sent as-is to Snowflake.

For example, if you have a tag cost_center and assign only the value finance to an object, the result in Snowflake is the single value finance without any concatenation.

Multiple values​

You can assign multiple values to a single tag for any object in Atlan. When multiple values are assigned, they're concatenated into a single string using a delimiter character.

For example, if you have a tag cost_center and assign the values finance, engineering, and sales to an object with comma as the delimiter, the result is the concatenated string engineering,finance,sales.

Sorting​

Tag values are sorted alphabetically before concatenation to maintain consistent ordering.

For example, if you have a tag environment with values production, development, and staging assigned to an object and use a comma (,) as your delimiter, Atlan sorts them alphabetically (development, production, staging) and concatenates them as: development,production,staging.

Reverse sync​

Concatenation and reverse sync apply at the schema level for imported Snowflake tags. When reverse sync is enabled, the concatenated tag values are synchronized back to the corresponding objects in Snowflake.

Updates and removals​

When you update or remove tag assignments in Atlan, these changes can be synchronized back to Snowflake and depend on the combination of reverse sync and concatenation settings:

  • When reverse sync is OFF: Snowflake isn't updated
  • When reverse sync is ON but concatenation is OFF: Only one tag value (typically the latest) is sent to Snowflake
  • When both reverse sync and concatenation are ON: All tag values are concatenated and sent as a single string

See also​