init

dbt/macros/materialization/table_if_rows_exist.sql

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+{% materialization table_if_rows_exist, adapter='oracle' %}
+
+    {%- set target_relation = this -%}
+
+    -- Count the number of rows in the source table
+    {#-- Use the compiled SQL of the model to count rows --#}
+    {%- set count_query %}
+        select count(*) as row_count from (
+            {{ model.compiled_sql }}
+        )
+    {%- endset %}
+
+    {#-- Execute the count query --#}
+    {%- set result = run_query(count_query) -%}
+    {%- set num_rows = result.columns[0].values()[0]|int -%}
+
+    {#-- Proceed only if there are rows --#}
+    {%- if num_rows > 0 -%}
+        {{ log(num_rows ~ ' rows found in source data. Executing model.', info=True) }}
+
+        {#-- collect hooks --#}
+        {% set pre_hooks = control_model_start() %}
+        {% set post_hooks = control_model_end('TRG') %}
+        
+        {#-- run pre_hooks --#}
+        {% do run_hooks(pre_hooks, inside_transaction=True) %}
+
+        {#-- Define a temporary relation with a unique name --#}
+        {%- set tmp_relation = api.Relation.create(
+            schema=target_relation.schema,
+            identifier=target_relation.identifier + '_tmp'
+        ) %}
+
+        {#-- Create a temporary table with the model's SQL --#}
+        {% set ctas_sql = 'CREATE TABLE ' ~ tmp_relation ~ ' AS ' ~ model.compiled_sql %}
+        {% call statement('main') %}
+           {{ ctas_sql }}
+        {% endcall %}
+
+        {#-- Drop the existing table if it exists --#}
+        {%- if adapter.get_relation(target_relation.database, target_relation.schema, target_relation.identifier) is not none -%}
+          {{ log('Dropping target table  ' ~ target_relation.identifier, info=True) }}
+          {% do run_query('DROP TABLE ' ~ target_relation.schema ~ '.' ~ target_relation.identifier) %}
+        {%- endif -%}
+
+        {#-- Rename the temporary table to the target name --#}
+        {{ log('Renaming temporary table to target table', info=True) }}
+        {% do run_query('ALTER TABLE ' ~ tmp_relation ~ ' RENAME TO ' ~ target_relation.identifier) %}
+
+        {#-- run post_hooks --#}
+        {% do run_hooks(post_hooks, inside_transaction=True) %}
+    {%- else -%}
+        {#-- Do nothing; leave the target table untouched --#}
+        {{ log('No rows in source data. Skipping model execution.', info=True) }}
+        {% call statement('main') %}
+            SELECT 1 FROM DUAL
+        {% endcall %}
+    {%- endif -%}
+
+    {#-- Return the target relation to dbt --#}
+    {{ return({'relations': [target_relation]}) }}
+
+{% endmaterialization %}
+