Specific Fields in a Query

[Ioio]

Hi, how can i make a query with specific fields from different databases, not all table information. How can i create a dynamic object to handle only these specific information.
Thanks

[QxOrm admin]

Hi,

For specific fields, you have to use the parameter const QStringList & columns for functions into namespace qx::dao.
The list of functions is available here :
http://www.qxorm.com/doxygen/html/group___qx_dao.html

Here a code of qxBlog project :

Code: Select all

// Fetch only property 'm_dt_creation' of blog
QStringList lstColumns = QStringList() << "date_creation";
list_blog lst_blog_with_only_date_creation;
daoError = qx::dao::fetch_all(lst_blog_with_only_date_creation, NULL, lstColumns);


[Ioio]

Thanks for your answer, it's clear. But, in the same example, if i want only a query with the following fields: Category_id, Category_Name, Blog_Text, and Author_name, should i use QStringList with the name of three different tables? Another question is, do you have a tool for autogenerate headers, relations, data type, etc from database, maybe using QtSql and QSqlDrive?
Thanks so much.
By

[QxOrm admin]

if i want only a query with the following fields: Category_id, Category_Name, Blog_Text, and Author_name, should i use QStringList with the name of three different tables?

No, when you want to query the database using more than 1 table (so you have some relations), you cannot specify columns to fetch. This is not supported by QxOrm library yet (version 1.1.7).
For your relations, you can :
1- lazy fetch (only id of each object are fetched, using qx::dao::fetch_all for example)
2- eager fetch (all properties of each object are fetched) => you can specify relations to eager fetch (using qx::dao::fetch_all_with_relation) or you can eager fetch all relations (using qx::dao::fetch_all_with_all_relation)

Another question is, do you have a tool for autogenerate headers, relations, data type, etc from database, maybe using QtSql and QSqlDrive?

There is no tool today to auto-generate some files.
It could be interesting, perhaps in a future release, I don't know yet...