- Android sqlite insert if not exists else update how to#
- Android sqlite insert if not exists else update update#
Note that if the ID field is set to autoincrement, then the IDs. When ID=1 exists, the ROLE will be unaffected. You can do this with a unique constraint & insert or ignore. INSERT OR REPLACE INTO Employee (id, role, name) When ID=1 does not exist, the name will be the default (NULL). This is why there's a subselect for the ID column: In the replacement case the statement would set it to NULL and then a fresh ID would be allocated.
Android sqlite insert if not exists else update update#
When ID=1 exists, the NAME will be unaffected. INSERT IF NOT EXISTS ELSE UPDATE ALTER TABLE ADD COLUMN IF NOT EXISTS in SQLite. Note that any field not in the insert list will be set to NULL if the row already exists in the table. 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. You want to conditionally insert, update, or delete records in a table depending on whether or not corresponding records exist. 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) ON DUPLICATE KEY UPDATE is non-destructive, in that it will only ever issue INSERT or UPDATE statements, but never DELETE.įor example, we have decided we wish to replace our id = 1 record of Green Eggs and Ham and revert it back to the original In Search of Lost Time record instead.Assuming 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. Unlike REPLACE – an inherently destructive command due to the DELETE commands it performs when necessary – using INSERT. ON DUPLICATE KEY UPDATE statement and clause. The alternative (and generally preferred) method for INSERTING into rows that may contain duplicate UNIQUE or PRIMARY KEY values is to use the INSERT. More information on using REPLACE can be found in the official documentation. The SELECT WHERE NOT EXISTS clause can only return a single row there is not a FROM clause - there is no way multiple rows can be returned. This is what the WHERE NOT EXISTS comes in. The new value 'ANI Received' is only inserted into table EVENTTYPE if it doesn't already exist in the table. Notice that even though we only altered one row, the result indicates that two rows were affected because we actually DELETED the existing row then INSERTED the new row to replace it. The intention is for EventTypeName to be unique. Seuss', 1960 ) Query OK, 2 rows affected ( 0. Upserts are a feature from newer sqlite3 versions that allows an insert to behave like an update if a conflicting row already exists. Mysql > REPLACE INTO books ( id, title, author, year_published ) VALUES ( 1, 'Green Eggs and Ham', 'Dr. The obvious purpose is to execute a large number of INSERT statements for a combination of data that is both already existing in the database as well as new data coming into the system.įor example, our books table might contain a few records already:
This means that an INSERT IGNORE statement which contains a duplicate value in a UNIQUE index or PRIMARY KEY field does not produce an error, but will instead simply ignore that particular INSERT command entirely. Using INSERT IGNORE effectively causes MySQL to ignore execution errors while attempting to perform INSERT statements.
Android sqlite insert if not exists else update how to#
MySQL provides a number of useful statements when it is necessary to INSERT rows after determining whether that row is, in fact, new or already exists.īelow we’ll examine the three different methods and explain the pros and cons of each in turn so you have a firm grasp on how to configure your own statements when providing new or potentially existing data for INSERTION.
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