sql update - How to temporarily break column uniqueness in SQLite? -


i've got simple table:

create table checkliststep (     checklist integer references checklist (id),      id        integer primary key autoincrement,      stepindex integer not null,      name      varchar not null,      unique (checklist, stepindex));

now want exchange 2 items' indexes. doing i'm breaking temporarily uniqueness of pair (checklist, stepindex). hoped, can in transaction, such after committing, constraints kept, doesn't work:

begin transaction; update checkliststep set stepindex = 0 id = 6; update checkliststep set stepindex = 1 id = 5; commit transaction;

causes:

unique constraint failed: checkliststep.checklist, checkliststep.stepindex

how write such update?

sqlite not have deferred unique constraints.

the pragma writable_schema dirty trick not work here because internal index corrupted if changed table without updating index.

the way use temporary value guaranteed unused:

begin; update checkliststep set stepindex = -99999999 id = 6; update checkliststep set stepindex = 1 id = 5; update checkliststep set stepindex = 0 id = 6; commit;

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