It cover key highlight and approach on Why Number declaration without precision and scale require refactor consideration and how to achieve it in Oracle to PostgreSQL Migration. Armor with automated approach to choose optimal numeric data type in PostgreSQL.

1. Don’t let Number data type be the
villain in your migrating journey.
Deepak Mahto
Feb 2023

2. Meet the Speaker
Deepak Mahto
Cloud Migration Consultant - Google Cloud

3. Oracle Number Characteristic

4. Number Data type and Tools.
Ispirer
Ora2pg
CompilerWorks

5. PostgreSQL - Numeric vs Integer

6. Number Recommender - Metadata based
Oracle Data
type
Oracle PRECISION(p)
Oracle
SCALE(s)
PostgreSQL
NUMBER(p) p < 5 0 OR NULL SMALLINT
NUMBER(p) p >=5 and p<10 0 OR NULL INTEGER
NUMBER(p) p >=10 and p<19 0 OR NULL BIGINT
NUMBER(p) p>=19 and P < 30 0 OR NULL NUMERIC(p)
NUMBER(p) p>=30 0 OR NULL NUMERIC(p)
NUMBER(p,s) p is not null s < 10 NUMERIC(p,s)
NUMBER(p,s) p is not null s > 10 NUMERIC(p,s)

7. Number Recommender - Sampling based
Oracle Data Type
Max Scale length
calculated
Data value sampled
PostgreSQL Data
Type
NUMBER 0
BETWEEN -9223372036854775808
AND 9223372036854775807
BIGINT
NUMBER
max_left_significant_digit + max_right_significant_digit
<=15
DOUBLE PRECISION
NUMBER > 38 NOT NULL NUMERIC
NUMBER <10 NOT NULL NUMERIC
NUMBER >10 NOT NULL NUMERIC
NUMBER NULL NULL DOUBLE PRECISION

8. Number Recommender
Recommender
SQL File
Connect and scan as per
Flags
Generate
Recommendation
MODIFY_TYPE
SAMPLE_NUMBER_DATA_TYPE:COL4:INTEGER,SAMP
LE_NUMBER_DATA_TYPE:COL5:BIGINT,SAMPLE_NU
MBER_DATA_TYPE:COL6:BIGINT,..........

9. Github repo - link

10. Thank you!
deepakmahto@google.com