Make index macros not recreate indexes on incremental models

CHANGELOG.md

@@ -4,6 +4,7 @@
 #### under the hood:
 
 - hotfix for regression introduced by [#126](https://github.com/dbt-msft/dbt-sqlserver/issues/126) that wouldn't surface syntax errors from the SQL engine [#140](https://github.com/dbt-msft/dbt-sqlserver/issues/140) thanks [@jeroen-mostert](https://github.com/jeroen-mostert)!
+- ensure that macros are not recreated for incremental models [#116](https://github.com/dbt-msft/dbt-sqlserver/issues/116) thanks [@infused-kim](https://github.com/infused-kim)
 - authentication now is case-insensitive and accepts both `CLI` and `cli` as options. [#100](https://github.com/dbt-msft/dbt-sqlserver/issues/100) thanks (@JCZuurmond)[https://github.com/JCZuurmond]
 - add unit tests for azure-identity related token fetching
 

dbt/include/sqlserver/macros/indexes.sql

@@ -108,26 +108,43 @@ select @drop_remaining_indexes_last = (
 
 {{ log("Creating clustered index...") }}
 
+{% set idx_name = this.table + '__clustered_index_on_' + columns|join('_') %}
+
+if not exists(select * from sys.indexes 
+                where 
+                name = '{{ idx_name }}' and 
+                object_id = OBJECT_ID('{{ this }}')
+)
+begin
+
 create
 {% if unique -%}
 unique
 {% endif %}
 clustered index
-    {{ this.table }}__clustered_index_on_{{ columns|join("_") }}
+    {{ idx_name }}
       on {{ this }} ({{ '[' + columns|join("], [") + ']' }})
-
+end
 {%- endmacro %}
 
 
 {% macro create_nonclustered_index(columns, includes=False) %}
 
 {{ log("Creating nonclustered index...") }}
 
+{% set idx_name = this.table + '__index_on_' + columns|join('_') %}
+
+if not exists(select * from sys.indexes 
+                where 
+                name = '{{ idx_name }}' and 
+                object_id = OBJECT_ID('{{ this }}')
+)
+begin
 create nonclustered index
-    {{ this.table }}__index_on_{{ columns|join("_") }}
+    {{ idx_name }}
       on {{ this }} ({{ '[' + columns|join("], [") + ']' }})
       {% if includes -%}
         include ({{ '[' + includes|join("], [") + ']' }})
       {% endif %}
-
+end
 {% endmacro %}