Pl/sql block problem: No data found error

sql

exception-handling

best-practices

debugging

byAnton Shumikhin·Nov 21, 2024

If a NO_DATA_FOUND error is sneaking up on you in PL/SQL, wrap your SELECT INTO statement in an EXCEPTION block. It's like a safety net, catching any instances when your data decided to play hide and seek.

BEGIN
  SELECT column INTO variable FROM table WHERE condition;
EXCEPTION WHEN NO_DATA_FOUND THEN
  variable := fallback_value; -- Aha! Data, didn't find you? I have a backup!
END;

Don't forget to tailor your WHERE clause and verify table data to dodge the ‘data not found’ bullet.

Bulletproofing your exception handling

The golden rules of exception handling

Initialize your variables before your investigations; it's like driving a car with zero on the odometer.

variable := initial_value; -- Like morning coffee, start fresh!

The best way to contain potential explosive exceptions? Treat each SELECT INTO statement as a potential suspect, and quarantine them with their own BEGIN/EXCEPTION/END block. Keeps everyone else safe!

Debugging tips: the detective's toolbox

Leave your breadcrumbs with DBMS_OUTPUT.PUT_LINE, by printing before running your query. Ever tried retracing your steps when lost?

DBMS_OUTPUT.PUT_LINE('Variable before SELECT: ' || TO_CHAR(variable)); -- "Dear diary..."

Data types and conditions: the suspect's description

Don't let your queries go rogue. Confirm variable and column data types are a match, and that your SELECT conditions adore your data.

Just exception blocks? Try a little diplomacy

Don't just shoot from the hip with EXCEPTION blocks. Court your variables gently, checking for null values with CASE or IF statements.

Structuring PL/SQL blocks like a pro

Wake up and smell the `NO_DATA_FOUND`

Expect NO_DATA_FOUND roaming around your code like a wandering nomad, and gear up accordingly. Don't bet on a sure thing; instead, confirm it exists with a trusty SELECT INTO.

Ensure your lifejacket fits

Utilize a CASE statement to flow through your variables, deftly navigating those fiery nulls, to ensure smooth sailing.

Experiment: variety, the spice of coding life

Diversify your approach to PL/SQL exceptions by employing mechanics like cursor attributes, for a smooth error-handling experience.

Facts: your sturdy foundation

Corrections? Amendments? Book errata to the rescue. Prioritize the tried and true over the vogue; sound programming is built on understanding, not memorization.

explain-codes / Sql / Pl/sql block problem: No data found error

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