In such scenarios, batch insert or updates can speed up the process. field_2,NEW.How to efficiently insert or update a lot of data in Android SQLite databaseĭatabase transactions are slow and in situations where there is need for thousands of records have to be inserted, inserting each record takes a lot of time and valuable resources. INSERT INTO table_one( field_1, field_2, field_3) Trigger to insert records into the underlying tables of a view However a trigger assigned to a view can be used to insert,update or delete records in underlying tables of the view. > WHERE ReqEquip.ReqNumber=ReqDetail.ReqNumber GROUP BY ReqDetail.ReqNumber >'$ ' || (ROUND(SUM(Quantity*ItemCost),2)) 'Req Total' 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. > ReqEquip.Requestor 'Requestor',ReqDate, Sqlite> CREATE VIEW 'ReqTotal' AS SELECT ReqEquip.ReqNumber 'Requisition', However in SQLite a view can not be used to add, update or delete the records in the underlying tables.ĬREATE VIEW view_name AS select_statement ĬREATE TEMPORARY VIEW database_name. > DELETE from ReqDetail WHERE ReqDetail.ReqNumber = OLD.ReqNumber Ī VIEW is a saved SELECT statement that can be used in much the same way as a table. > THEN RAISE(ABORT, 'update on table ReqDetail violates foreign key')ĭelete records from a child table when a record from the parent table is deletedĭELETE FROM child_table WHERE child_table. >WHERE ReqEquip.ReqNumber= NEW.ReqNumber) ISNULL) > WHEN ((SELECT ReqEquip.ReqNumber FROM ReqEquip Sqlite>CREATE TRIGGER ReqNumUp BEFORE UPDATE ON ReqDetail FOR EACH ROW BEGIN SQL error: This Requisition number does not exist in the ReqEquip table.ĬREATE TRIGGER trigger_name BEFORE UPDATE ON child_table FOR EACH ROW BEGIN Sqlite> insert into ReqDetail(ReqNumber,StockNumber,Quantity)values(2000,51001,15) Each INSERT and UPDATE operation requires a. > THEN RAISE(ABORT, 'This Requisition number does not exist in the ReqEquip table.') The hook must be registered on the connection being used which requires clients to manually integrate this code. > WHEN ((SELECT ReqEquip.ReqNumber FROM ReqEquip WHERE ReqEquip.ReqNumber= NEW.ReqNumber) ISNULL) Sqlite> CREATE TRIGGER ReqNumIn BEFORE INSERT ON ReqDetail BEGIN Delete: Similar to insert and update, delete function is available in SQLiteDatabase class, So delete is very similar to update function apart from. primary_key FROM parent_table WHERE parent_table. Using Triggers to Enforce Referential IntegrityĬREATE TRIGGER trigger_name BEFORE INSERT ON child_table BEGIN Sqlite> select StockNumber,OnHandQuan,Descrip from inventory where StockNumber =75149 ħ5149|89|Ball Point Pens Blue Fine tip, 12pack Sqlite> INSERT INTO ReqDetail(ReqNumber,StockNumber,Quantity,ItemCost) VALUES(1003,75149,3,0.77) > WHERE inventory.StockNumber = NEW.StockNumber > UPDATE inventory SET OnHandQuan = (OnHandQuan- NEW.Quantity) Sqlite> CREATE TRIGGER inventoryupdate AFTER INSERT ON ReqDetail BEGIN Sqlite> select StockNumber,OnHandQuan,Descrip from inventory where StockNumber = 75149 ħ5149|92|Ball Point Pens Blue Fine tip, 12pack UPDATE inventory SET OnHandQuan = ( OnHandQuan - NEW.Quantity) WHERE inventory.StockNumber = NEW.StockNumber This trigger automatically updates the inventory table by subtracting the Quantity of items requisitioned from the OnHandQuan value when an insert statement adds a record to the ReqDetail table.ĬREATE TRIGGER inventoryupdate AFTER INSERT ON ReqDetail BEGIN Once created, triggers cannot be modified, to make changes the trigger must be dropped and then recreated. Triggers are deleted when the table that they are associated with is dropped or they can be deleted with a DROP TRIGGER statement. Each trigger must have a name that is unique to the database. Helpers for insert/query/update/delete queries DB operation executed in a. If it does not exist, I want to INSERT the record with the default (NULL) value for the fourth column. What is a trigger? In SQL, a trigger is a sql statement or series of sql statements that are executed automatically in response to a specified event such as the update of or creation or deletion of a table or record. Flutter plugin for SQLite, a self-contained, high-reliability, embedded. Insert Update stored proc on SQL Server Is there some clever way to do this in SQLite that I have not thought of Basically I want to update three out of four columns if the record exists.
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