SQL · Theory

INSERT IGNORE

Theory

38/439

INSERT IGNORE

INSERT IGNORE INTO students … skips rows that would error (duplicate key, some data issues) and continues. You don’t get a hard fail. Useful for loading a file with a few duplicates.

You also won’t notice real problems. Check ROW_COUNT() / warnings. Prefer fixing duplicates over IGNORE in app code.

Trap — INSERT IGNORE hiding NOT NULL / type errors you should fix.

On the example next to this theory — INSERT IGNORE — iNSERT adds rows. List columns explicitly for clarity.

Exam tip

INSERT IGNORE skips duplicate-key rows. Don’t hide bugs with it.

INSERT IGNORE — sample query

CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT, price REAL);
INSERT INTO products (id, name, price) VALUES
  (1, 'Mouse', 499),
  (2, 'Keyboard', 999);
SELECT * FROM products;

INSERT IGNORE — iNSERT adds rows. List columns explicitly for clarity.

Short notes

DefINSERT IGNORE skips offending rows instead of aborting.
RuleOK for dirty loads. Bad as everyday app logic.
TrapSwallowing real errors.

SQL · Theory

INSERT IGNORE

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Theory

38/439

INSERT IGNORE

INSERT IGNORE INTO students … skips rows that would error (duplicate key, some data issues) and continues. You don’t get a hard fail. Useful for loading a file with a few duplicates.

You also won’t notice real problems. Check ROW_COUNT() / warnings. Prefer fixing duplicates over IGNORE in app code.

Trap — INSERT IGNORE hiding NOT NULL / type errors you should fix.

On the example next to this theory — INSERT IGNORE — iNSERT adds rows. List columns explicitly for clarity.

Exam tip

INSERT IGNORE skips duplicate-key rows. Don’t hide bugs with it.

INSERT IGNORE — sample query

CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT, price REAL);
INSERT INTO products (id, name, price) VALUES
  (1, 'Mouse', 499),
  (2, 'Keyboard', 999);
SELECT * FROM products;

INSERT IGNORE — iNSERT adds rows. List columns explicitly for clarity.

Short notes

DefINSERT IGNORE skips offending rows instead of aborting.
RuleOK for dirty loads. Bad as everyday app logic.
TrapSwallowing real errors.

INSERT IGNORE

INSERT IGNORE — sample query

Short notes

Questions

INSERT IGNORE

INSERT IGNORE — sample query

Short notes

Questions