fix: teradata NUMBER with no precision/scale, small doc fix after Ibi…

…s upgrade (#914)

Added issue #915 - which will address the testing request
Urgent customer request.

Sundar Mudupalli

README.md

@@ -657,12 +657,12 @@ required, if any, with the 'params' block as shown below:
     target_calculated_columns:
     - start_time
     type: custom
-    ibis_expr: ibis.expr.api.TimestampValue.strftime
+    ibis_expr: ibis.expr.types.TemporalValue.strftime
     params:
     - format_str: '%m%d%Y'
 ```
 
-The above block references the [TimestampValue.strftime](https://ibis-project.org/reference/expressions/timestamps/#ibis.expr.types.temporal.TemporalValue.strftime) Ibis API expression.
+The above block references the [TemporalValue.strftime](https://ibis-project.org/reference/expressions/timestamps/#ibis.expr.types.temporal.TemporalValue.strftime) Ibis API expression.
 See the [Examples page](https://github.com/GoogleCloudPlatform/professional-services-data-validator/blob/develop/docs/examples.md#sample-row-validation-yaml-with-custom-calc-field)
 for a sample YAML with a custom calculated field.
 

third_party/ibis/ibis_teradata/datatypes.py

@@ -76,16 +76,33 @@ def to_ibis_from_CV(cls, col_data, return_ibis_type=True):
 
     @classmethod
     def to_ibis_from_N(cls, col_data, return_ibis_type=True):
-        return cls.to_ibis_from_D(col_data, return_ibis_type=return_ibis_type)
+        precision = int(
+            col_data.get("DecimalTotalDigits", col_data.get("Decimal Total Digits", 38))
+        )
+        scale = int(
+            col_data.get(
+                "DecimalFractionalDigits", col_data.get("Decimal Fractional Digits", 38)
+            )
+        )
+        if return_ibis_type:
+            # No precision or scale specified
+            if precision == -128 or scale ==-128:
+                return dt.Decimal()
+            return dt.Decimal(precision, scale)
+
+        if precision == -128 or scale ==-128:
+            return "DECIMAL"
+
+        return "DECIMAL(%d, %d)" % (precision, scale)
 
     @classmethod
     def to_ibis_from_D(cls, col_data, return_ibis_type=True):
         precision = int(
-            col_data.get("DecimalTotalDigits", col_data.get("Decimal Total Digits", 20))
+            col_data.get("DecimalTotalDigits", col_data.get("Decimal Total Digits", 5))
         )
         scale = int(
             col_data.get(
-                "DecimalFractionalDigits", col_data.get("Decimal Fractional Digits", 4)
+                "DecimalFractionalDigits", col_data.get("Decimal Fractional Digits", 0)
             )
         )
         if return_ibis_type: