#Sqlitestudio foreign key to same table code#

a detail query called qrySales that selects from the SALES table.a master query called qr圜ustomers selects from the CUSTOMER table.use one connection, 1 transaction, but 2 queries, 2 data sources.a SALES table with a CUST_NO integer field that is a foreign key linking to the CUST_NO field in the CUSTOMER table.a CUSTOMER table with an integer primary key CUST_NO and other fields.Zeos) please check with their documentation.Įxample from the EMPLOYEE database (as used in SQLdb Tutorial0 and other tutorials): It may also apply to other database layers (e.g.

#Sqlitestudio foreign key to same table code#

The approach below applies to both Lazarus and FPC code that uses the built in SQLdb Package database layer.

You can use the datasource property in the detail dataset to link to the master dataset. In our example below we'll work with a customer table and an order table. In the detail table it is called a foreign key.Ĭlassical examples of master/detail relations are: So this key exists in both the master and detail table. The filtering works because the detail table contains an identifier from the master table, usually the master table's primary key. The countries table could be master, and cities table could be detail. If you select a country and want to see all its cities, that is a good job for Master/Detail. The dataset that is used to filter the data is called Master and the filtered dataset is called Detail.įor example, countries have many cities. It is a model that uses data from one dataset to filter data in another dataset. It means that one record in a table/dataset can be related to many records in another table/dataset. In relational databases the master-detail concept is also called one-to-many or 1:N.

4 Delete all Detail records if Master record is deleted.

2.2 Using detail parameters that do not filter using master data.

2.1 Adding detail records with the right foreign key.