Is there a way to populate column based on conditions stored as rows in a table - sql

Question

I am working on a project that has a C# front end that will be used to select a file for importing into an MSSQL SQL Database. In the table there will be an additional column called 'recommendedAction' (tinyint - 0-5 only)
I would like to have sql fill in the 'recommendedAction' column based on criteria in a different table.
Is there a way that when SQL is importing (SSIS or pure TSQL) it could read the values of a table and fill in the 'action' based on the criteria? Or is this something that should be done in the C# frontend?
EDIT
SQL table structure for imported data (with additional column)
Create Table ImportedData (
Column1 INT Identity,
Column2 VARCHAR(10) NOT NULL,
Column3 CHAR(6) NOT NULL,
RecommendedAction TINYINT NOT NULL
)
Table structure of recommended action criteria
Create Table RecommendedActions(
ID INT Identity,
ActionID TINYINT NOT NULL, --value to put in the RecommendedAction column if criteria is a match
CriteriaColumn VARCHAR(255) NOT NULL --Criteria to match against the records
)
Example records for RecommendedActions
ID ActionID CriteriaColumn
1 2 'Column2 LIKE ''6%'''
2 3 'Column2 LIKE ''4%'''
Now when a new set of data is imported, if Column2 has a value of '6032' it would fill in a RecommendedAction of 2

Answer 1

Many ways exist. For example you can insert into the tb table a value selected from the ta table according to criteria.
Example setup
create table ta(
Id int,
val int);
insert into ta(ID, val) values
(1, 30)
,(2, 29)
,(3, 28)
,(4, 27)
,(5, 26);
create table tb
(Id int,
ref int);
Example insert
-- parameters
declare #p1 int = 1,
#p2 int = 27;
-- parameterized INSERT
insert tb(Id, ref)
values(#p1, (select ta.id from ta where ta.val=#p2));

Answer 2

Below added Stored procedure will do the job. It gets the Action column value based on the Column2 parameter and insert into the ImportedData table. You can execute this Stored procedure inside the C# code with required parameters. I added sample execute statements for to test the query.
Sample data inserted to the RecommendedActions Table:
INSERT INTO RecommendedActions
VALUES
(2, 'Column2 LIKE ''6%''')
,(3, 'Column2 LIKE ''4%''')
Stored Procedure Implementation :
CREATE PROCEDURE Insert_ImportedData(
#Column2 AS VARCHAR(10)
,#Column3 AS CHAR(3)
)
AS
BEGIN
DECLARE #RecommendedAction AS TINYINT
SELECT #RecommendedAction = ActionID
FROM RecommendedActions
WHERE SUBSTRING(CriteriaColumn, 15, 1) = LEFT(#Column2 , 1)
INSERT INTO ImportedData VALUES (#Column2,#Column3,#RecommendedAction)
END
GO
This is the execute statement for the Above Stored procedure
EXEC Insert_ImportedData '43258' , 'ATT'
EXEC Insert_ImportedData '63258' , 'AOT'

Answer 3

you can use sqlalchemy in python and load your data into a dataframe then append the dataframe to the sql table. You can set the dtype for each of the field datatype in the read_csv using a dictionary. Loading data with Python is super powerful because the bulk load is fast. Use your c# code to build the csv file using stream io and use linq to for your conditions for data fields. Then use python to load your csv.
import pandas as pd
from sqlalchemy import create_engine
engine = create_engine(connectionstring)
df = pd.read_csv("your_data.csv", header=None)
df.columns = ['field1', 'field2', 'field3']
df.to_sql(name="my_sql_table", con=connection, if_exists='append', index=False)