From c2f5f7318d5a6a764ef99e5720b3a594464769fd Mon Sep 17 00:00:00 2001 From: Harrissou Sant-anna Date: Tue, 17 Oct 2023 03:21:33 +0200 Subject: [PATCH] Apply suggestions from review Co-authored-by: Denis Rouzaud --- .../working_with_vector/joins_relations.rst | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) diff --git a/docs/user_manual/working_with_vector/joins_relations.rst b/docs/user_manual/working_with_vector/joins_relations.rst index ac09081bed6..16799ff7e8d 100644 --- a/docs/user_manual/working_with_vector/joins_relations.rst +++ b/docs/user_manual/working_with_vector/joins_relations.rst @@ -26,8 +26,8 @@ QGIS provides tools to handle any of these associations, such as: Joins and relations are technical concepts borrowed from databases to get the most out of data stored in tables by combining their contents. - The idea is that features (rows) of different layers (tables) can belong to each other. - The links between the features can be of one-to-one type (joins) or one/many to many (relations). + The idea is that features (rows) of different layers (tables) can be associated to each other. + The number of rows which are matching each other can be of any value (zero, one, many). .. index:: Joins, Foreign key @@ -36,9 +36,9 @@ QGIS provides tools to handle any of these associations, such as: Joining features between two layers ==================================== -**Joins** allow you to associate features of the current layer +**Joins** in QGIS allow you to associate features of the current layer to features from another loaded vector layer. -Whether they are spatially enabled and their geometry type does not matter. +Whether they are spatially enabled and the type of geometry do not matter. The join is based on an attribute that is shared by the layers, in a one-to-one relationship. To create a join on a layer (identified below as ``target layer``): @@ -61,7 +61,7 @@ To create a join on a layer (identified below as ``target layer``): Join an attribute table to an existing vector layer The steps above will create a join, -where **ALL** the attributes of the first matching feature in the join layer +where **ALL** the attributes of the **first matching feature** in the join layer is added to the target layer's feature. The following logic is used to pair features during a join process: @@ -103,12 +103,6 @@ QGIS provides some more options to tweak the join: * |unchecked| :guilabel:`Custom field name prefix` for joined fields, in order to avoid name collision -QGIS currently has support for joining non-spatial table formats supported by GDAL -(e.g., CSV, DBF and Excel), delimited text and the PostgreSQL providers. - -.. is the above still true? No more supported formats (oracle, mssql, ...)??? - - .. index:: Relations, Foreign key .. _vector_relations: @@ -130,7 +124,8 @@ From there, you can: with the dedicated tools in the action drop-down menu. .. note:: There is no simple way yet to edit a non-polymorphic relation once it has been created. - To modify a relation you will have to remove and recreate it from scratch. + Only the name can be edited with a double-click. + For any other parameters of such a relation you will have to remove and recreate it. * |symbologyAdd| :guilabel:`Discover relations`: QGIS is able to discover existing relations from supported database formats (PostgreSQL, GeoPackage, ESRI File Geodatabase, ...).