To Dynamic SQL or Not - oracle

Question

When doing an update, we want to do a concurrency check on the ORA_ROWSCN (Oracle db BTW). So I was thinking of creating a function, where you pass in the ora_rowscn you have, table name, column name and an ID. The function would check would do a select statement based on the table, column and id you've passed in and if the returned ora_rowscn is different from the one you passed in, return a true or false is it's the same.
I do validity check on the table_name and column_name passed in to make sure they exists first.
FUNCTION ConcurrencyCheck (
pi_orarowscn_in IN NUMBER,
pi_table_name IN VARCHAR2,
pi_column_name IN VARCHAR2,
pi_id IN NUMBER
)
RETURN BOOLEAN IS
r_data_out_of_date BOOLEAN := false;
ln_orarowscn_current NUMBER := 0;
lv_sql VARCHAR2(300) := '';
lv_column VARCHAR(20) := '';
lv_table VARCHAR(20) := '';
BEGIN
SELECT table_name INTO lv_table from ALL_TABLES WHERE TABLE_NAME = pi_table_name;
IF lv_table = '' THEN
RAISE NO_DATA_FOUND;
ELSE
SELECT column_name INTO lv_column from USER_TAB_COLUMNS WHERE TABLE_NAME = pi_table_name AND COLUMN_NAME = pi_column_name;
IF lv_column = '' THEN
RAISE NO_DATA_FOUND;
ELSE
lv_sql := 'select ORA_ROWSCN from ' || pi_table_name || ' where ' || pi_column_name || ' = ' || pi_id || '';
EXECUTE IMMEDIATE lv_sql INTO ln_orarowscn_current;
IF ln_orarowscn_current <> pi_orarowscn_in THEN
r_data_out_of_date := true;
END IF;
END IF;
END IF;
RETURN r_data_out_of_date;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RAISE;
WHEN OTHERS THEN
RAISE;
END ConcurrencyCheck;
I do not like the dynamic SQL that I have there. I would much rather (not have dynamic SQL but... ) have it like the following:
lv_sql := 'select ORA_ROWSCN from :table_name where :column_name = :id';
EXECUTE IMMEDIATE lv_sql INTO ln_orarowscn_current USING pi_table_name, pi_column_name, pi_id;
but I keep getting an SQL error saying the table is wrong
The other solution is to create a sub-function for ALL the tables that would return the ORA_ROWSCN for each and a IF ELSE in the main function to call each.
I'm looking for best practice here. Is this a time where dynamic SQL is acceptable? Or should I go the "long" route and create a ton of functions/procedures for each table?
Thank you!

Answer 1

As for the best practices, in these cases it's recommended to use the sys.dbms_assert package.
FUNCTION ConcurrencyCheck(
pi_orarowscn_in IN NUMBER,
pi_table_name IN VARCHAR2,
pi_column_name IN VARCHAR2,
pi_id IN NUMBER
)
RETURN BOOLEAN IS
ln_orarowscn_current NUMBER := 0;
lv_sql VARCHAR2(300) := '';
BEGIN
lv_sql := '
select X.ora_rowscn
from '||sys.dbms_assert.sql_object_name(pi_table_name)||' X
where X.'||sys.dbms_assert.simple_sql_name(pi_column_name)||' = :pi_id
';
execute immediate lv_sql
into ln_orarowscn_current
using in pi_id;
return ln_orarowscn_current <> pi_orarowscn_in;
END ConcurrencyCheck;
Note: If I were in your place, I'd give myself the initial hard time of implementing a metadata-driven code generator for the package of one-check-per-one-table functions that would be, as you may have guessed, static PL/SQL code – giving you all those nice compile-time syntax/semantic checks.