Delete

Delete DuckDB rows through Diesel: diesel::delete with a filtered target, deleting all rows, the unscoped-delete gotcha, and returning deleted values.

Removing rows with diesel::delete. Portable Diesel on the DuckDB backend.

Deleting matching rows

Pass a filtered table to diesel::delete:

use diesel::prelude::*;

diesel::delete(products::table.filter(products::id.eq(2))).execute(&mut conn)?;

diesel::delete(products::table.filter(products::price.lt(1.0))).execute(&mut conn)?;

.execute returns the number of rows deleted.

DuckDB-only predicates work in the filter once the DSL prelude is imported — see Operators:

use better_duck_diesel::dsl::*;

diesel::delete(products::table.filter(products::name.ilike("tmp-%"))).execute(&mut conn)?;

Deleting all rows

A delete with no filter removes every row:

diesel::delete(products::table).execute(&mut conn)?; // all rows

This is the single most common accidental data loss in Diesel. diesel::delete(table) without .filter truncates the table. Scope every delete with .filter(...) unless you really mean “delete everything”.

Returning deleted values

Chain .returning(...) with get_result/get_results to read columns from the rows that were deleted:

let removed: Vec<(i32, String)> = diesel::delete(products::table.filter(products::price.lt(1.0)))
    .returning((products::id, products::name))
    .get_results(&mut conn)?;

See RETURNING.

See also

Update

Modify rows instead of removing them.

RETURNING

Read values back from a delete.

Transactions

Make a multi-step delete atomic.

Select

Preview what a filter matches before deleting.