Sergiu posted a good explanation of the DatabaseList and DatabaseTree usage, which I must admit is a bit obscure for XWiki newbies :
First, a bit of introduction on DBList and DBTreeList. StaticList properties, when edited, allow the user to select one of the predefined values (or more, if the property has "multiple select" = true). DBList does something similar, allows the user to select one or more values from a list of values, but the list is not predefined, it is populated with values from the database. DBTreeList does the same as DBList, but also induces a pseudo-hierarchy in the option list, displaying the options as a tree. DBList and DBTreeList properties work in two ways. One is with an hql query, which allows complete flexibility on what you want to select. For DBList you select one or two columns. The first column is the list of possible values that get into the option list. The second (optional) column allows to separate the actual value that gets stored in the database, and the values that are displayed to the user. This allows, for example, to store XWiki.JohnDoe in the database, but to display "Doe, John" in the interface. If only one column is selected, the value displayed is the same as the value used internally. DBTreeList queries must select 3 columns. The first two are the same as for DBList, while the 3rd column defines the child<->parent relations. Selected rows that have null or an empty string on the third column will be considered the roots of the tree. Rows that have a value "X" on the third column will be inserted as child nodes of the node with value "X" (the first column). The second way to define the option lists is by using the fields: XWiki Class Name, Id Field Name, Value Field Name and Parent Field Name. Using those fields, the XWiki platform constructs the following hql queries: select idprop.value, valueprop.value, parentprop.value from XWikiDocument doc, BaseObject obj, StringProperty idprop, StringProperty valueprop, StringProperty parentprop.value where obj.name = doc.name and obj.className = "value entered in Class name" and idprop.id.id = obj.id and idprop.id.name = "value entered in Id Field Name" and valueprop.id.id = obj.id and valueprop.id.name = "value entered in Value Field Name" and parentprop.id.id = obj.id and parentprop.id.name = "value entered in Parent Field Name" So, it selects from objects of a given type (XWiki Class) 3 properties (of storage type String, read bellow what this means). As a special case, you can use "doc.<some doc property>" or "obj.<some object property>" instead of property names, and the query is adapted accordingly. In the case of DBList, only 2 columns are selected, as the Parent property is not used/defined. String storage type means: - either a property of type String - or a property of type StaticList, DBList or DBTreeList with multipleSelect = false If you want to use the DBTreeList, you must model your data so that they will allow these kind of queries. Hope this will help, cheers Hoani CROSS -- Globotraders Tahiti founder [http://globotraders-tahiti.com] hel-o wrote: > > Hi, > > and thanks for your response. I am aware of that documentation but i was > looking for a more detailed desription of the available properties. > > Is it possible to make a Data Base Property that shows a Object of another > Class a link to that Object? > > Thanks > Helmut > > > Jean-Vincent Drean-3 wrote: >> >> On Sun, Dec 14, 2008 at 6:28 PM, hel-o <[email protected]> wrote: >>> >>> Hi, >>> >>> is there a documentation for the existing property types of a class >>> available? >>> I found the tutorial about creating a class but no discription of the >>> property types. >> >> See http://platform.xwiki.org/xwiki/bin/view/DevGuide/DataModel >> >>> As i understand it deleting a property of a class is not possible. Is >>> this >>> feature planned? >>> >> >> Yes, it is not possible yet. This problem is known and will be >> addressed but it is not trivial and doesn't have a high priority. >> The usual workaround is to rename properties (to something like >> unused_string_1 for example). >> >> JV. >> _______________________________________________ >> users mailing list >> [email protected] >> http://lists.xwiki.org/mailman/listinfo/users >> >> > > ----- Hoani CROSS http://globotraders-tahiti.com Globotraders Tahiti Founder -- View this message in context: http://n2.nabble.com/Documentation-Class-Propertys-tp1655023p1667603.html Sent from the XWiki- Users mailing list archive at Nabble.com. _______________________________________________ users mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/users
