Sqlite insert update9/11/2023 Note how the ts column is completely missing on all sides – because it has a DEFAULT value, SQLite will just do the right thing in any case, so I don’t have to take care of it myself. Here, if a row did not previously exist, old.id will be NULL and SQLite will then assign an ID automatically, but if there already was such a row, old.id will have an actual value and this will be reused. The key is the use of INSERT SELECT with a left outer join, to join an existing row to the new values. The exact form of this query can vary a bit. SELECT old.id, new.name, new.title, old.content, new.authorįROM new LEFT JOIN page AS old ON new.name = old.name INSERT OR REPLACE INTO page (id, name, title, content, author) I achieve a true UPSERT with the following construct: WITH new (name, title, author) AS ( VALUES('about', 'About this site', 42) ) But when updating an existing row based on its name, I want it to continue to have the old ID value (obviously!). Note in particular that name is the natural key of the row – id is used only for foreign keys, so the point is for SQLite to pick the ID value itself when inserting a new row. To illustrate it I will assume the following schema: CREATE TABLE page (Īuthor INTEGER NOT NULL REFERENCES user (id), Here’s an approach that will scale well to any amount of columns on either side. If you want to preserve a lot of columns, it gets too cumbersome fast. INSERT OR REPLACE INTO Employee (id, name, role)ĬOALESCE((SELECT role FROM Employee WHERE id = 1), 'Benchwarmer')Įric B’s answer is OK if you want to preserve just one or maybe two columns from the existing row. When ID=1 does not exist, the role will be set to 'Benchwarmer' instead of the default value. When ID=1 exists, the ROLE will be unaffected. INSERT OR REPLACE INTO Employee (id, role, name) When ID=1 does not exist, the name will be the default (NULL). When ID=1 exists, the NAME will be unaffected. GOOD but tedious: This will update 2 of the columns. UPSERT in SQLite follows the syntax established by PostgreSQL. UPSERT is a special syntax addition to INSERT that causes the INSERT to behave as an UPDATE or a no-op if the INSERT would violate a uniqueness constraint. UPSERT support in SQLite! UPSERT syntax was added to SQLite with version 3.24.0! the NAME column will be set to NULL or the default value: INSERT OR REPLACE INTO Employee (id, role) Perhaps I should use the select to read the 4th column (Blob3) and then use REPLACE to write a new record blending the original 4th Column with the new data for the first 3 columns?Īssuming three columns in the table: ID, NAME, ROLEīAD: This will insert or replace all columns with new values for ID=1: INSERT OR REPLACE INTO Employee (id, name, role)īAD: This will insert or replace 2 of the columns. UPDATE I am guessing is slow compared to INSERT, but how does it compare to SELECT using the Primary key? Destroy the statement object using sqlite3_finalize().Reset the statement using sqlite3_reset() then go back to step 2 and repeat.Bind values to host parameters using sqlite3_bind_ interfaces.Create the object using sqlite3_prepare_v2().The life of a statement object goes something like this: UPDATEs in SQLite when binding data are a complete transaction, meaningĮach sent row to be updated requires: Prepare/Bind/Step/Finalize statements unlike the INSERT which allows the use of the reset function So I assume Blob1 and Blob2 would not be replaced (as desired) Id INTEGER PRIMARY KEY ON CONFLICT REPLACE,īut the first two blobs will not cause a conflict, only the ID would If it was, I have three columns so it would actually look like: CREATE TABLE table1( I have not built a demo to test it, but it doesn't seem to be supported. I cannot confirm that syntax on the SQLite site for TABLE CREATE. (I am trying to avoid the overhead of SELECT in order to determine if I need to UPDATE or INSERT obviously) The ID is a primary key, so there will only ever be one record to UPSERT. If it does not exist, I want to INSERT the record with the default (NULL) value for the fourth column. Is there some clever way to do this in SQLite that I have not thought of?īasically I want to update three out of four columns if the record exists.
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