![]() ![]() One alternative is to have SQLite ignore the offending row. We can see that the table only contains the original row. We can verify that nothing was inserted by running a SELECT statement against the table. INSERT OR ABORT INTO Products VALUES (1, 'Wrench', 12.50) This is the equivalent of using the OR ABORT option. Result: Error: UNIQUE constraint failed: Products.ProductIdĪn error was returned and nothing was inserted. ![]() INSERT INTO Products VALUES (1, 'Wrench', 12.50) Example 1 – Abort (Default Behaviour)Īs mentioned, the default behaviour for SQLite is to abort the INSERT operation and return an error. Now we can run through the various scenarios of inserting data into that table that violates the primary key constraint. We currently have one row, with a ProductId of 1. INSERT INTO Products VALUES (1, 'Hammer', 8.00) Let’s create a simple table and add one row. The examples on this page use the second option – I create the table without the ON CONFLICT clause, and I instead specify OR on the INSERT statement. When you use this option, the syntax is different you use OR instead of ON CONFLICT. This allows you to take advantage of the clause even when the table wasn’t created with it. Doing that will determine how all INSERT operations are treated.Īnother option is to use the clause on the INSERT statement whenever you try to insert data into the table. One option is to use this clause in the CREATE TABLE statement when creating the table. By default, when you try to do this, the operation will be aborted and SQLite will return an error.īut you can use the ON CONFLICT clause to change the way SQLite deals with these situations. This article provides examples of how this clause can be used to determine how to handle primary key constraint conflicts.īy “primary key constraint conflicts”, I mean when you try to insert a duplicate value into a primary key column. In particular, the clause applies to UNIQUE, NOT NULL, CHECK, and PRIMARY KEY constraints. UNIQUE constraint failed: devices.logical_address, devices.SQLite has a non-standard SQL extension clause called ON CONFLICT that enables us to specify how to deal with constraint conflicts. The unique constraint prevents duplicates: insert into devices (device_id,logical_address, physical_location_id, district) Insert into physical_locations (physical_location_id, name, district)ĭrawback is that you have to add district to devices: insert into devices (device_id,logical_address, physical_location_id, district) ![]() References physical_locations (district, physical_location_id) , foreign key (district, physical_location_id) Now it is possible to reference that in a foreign key (guarantees that the same location, district is used: create table devices , UNIQUE (district, physical_location_id) ( physical_location_id char(2) not null - primary key Is there a way to enforce this using a unique constraint or by restructuring my tables, or will I need something more advanced?Ī common trick is to add a unique constraint to physical_locations: create table physical_locations Then it is possible for a device to have a location with a district that does not match the district of the logical_address. One thought I had was to create another logical_address table with address and district columnns, with a unique constraint on both and simply reference device logical addresses to these entries with a unique constraint, but that introduces the same issue in another area. Alternatively, I am not sure how to structure my data to maintain this requirement without such an issue. I just don't know how to reference this column in a foreign key referenced table for a UNIQUE constraint. So for example, consider these records: physical_locationsġ 100 LA <-this is okay, same district as 2 but different addressĢ 201 LB <-this is okay, same district as 1 but different addressģ 100 LC <-this is also okay, same address as 1 but different districtĤ 100 LD <-this is NOT OKAY, same address AND same district as 3 What I need to do is enforce uniqueness of the logical_address column in the devices table but ONLY within the district associated with its location record. Physical_location (Foreign Key (physical_locations.id))Īs shown, the devices table references its location to the physical locations table.
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