Relations

This command opens the Relation Design window, which allows you to define relationships between various database tables.

Here you can link together tables from the current database through common data fields. Click the New Relation icon to create the relationships, or simply drag-and-drop with the mouse.

Pro přístup k tomuto příkazu...

V okně databázového souboru zvolte Nástroje - Relace.


note

Tato funkce je dostupná jen tehdy, pokud pracujete s relační databází.


When you choose Tools - Relationships, a window opens in which all the existing relationships between the tables of the current database are shown. If no relationships have been defined, or if you want to relate other tables of the database to each other, then click on the Add Tables icon. The Add Tables dialog opens in which you can select the tables with which to create a relation.

Ikona Přidat tabulku

Vložit tabulky

note

If the Relation Design window is open, the selected tables cannot be modified, even in Table Design mode. This ensures that tables are not changed while the relations are being created.


The selected tables are shown in the top area of the relation design view. You can close a table window through the context menu or with the Delete key.

Posunutí a změna velikosti tabulky

Tabulky je možné podle potřeby uspořádávat a měnit jejich velikost. Jestliže chcete tabulku posunout, přetáhněte její horní okraj na požadovanou pozici. Okno tabulky zvětšíte nebo zmenšíte tak, že umístíte kurzor myši na jeho ohraničení nebo roh a tažením myši jej upravíte na požadovanou velikost.

Primary key and foreign keys

If you want to define a relation among the various tables, you should enter a primary key that uniquely identifies a data field of an existing table. You can refer to the primary key from other tables to access the data of this table. All data fields referring to this primary key will be identified as a foreign key.

All data fields referring to a primary key will be identified in the table window by a small key symbol.

Define relations

All existing relations are shown in the relations windows by a line that connects the primary and foreign key fields. You can add a relation by using drag-and-drop to drop the field of one table onto the field of the other table. A relation is removed again by selecting it and pressing the Delete key.

Alternatively, you can also click the New Relation icon in the top area of the relation field and define the relation between two tables in the Relations dialog.

Ikona Nová relace

Nová relace

warning

If you use LibreOffice as the front-end for a relational database, the creation and deletion of relationships is not placed in an intermediate memory by LibreOffice, but is forwarded directly to the database.


By double-clicking a connection line, you can assign certain properties to the relation. The Relations dialog opens.

Podpořte nás!