Virtual Tables - Lianja Cloud Server
Contents
See Also
- Syntax for the CREATE VIRTUALTABLE and ALTER VIRTUALTABLE Commands
- Properties and Methods of the CursorAdapter Class
Primary Key Required
Virtual tables used with the Lianja Cloud Server must have a unique primary key specified in the virtual table definition.
See Virtual Tables for an introduction to virtual table creation. To add a primary key to an existing virtual table, open the database in the Data Workspace, select the virtual table name then right-click Modify virtual table ... to open the dialog and add the key.
The primary key can also be specified in the CREATE VIRTUALTABLE and ALTER VIRTUALTABLE commands.
Note: keyfieldlist and primarykey are synonymous.
// create virtual table and specify primary key create virtualtable vt_actors connstr "lianja_mysqltest" alias "vt_actors" primarykey "actor_id"; properties "keepalive=1;rowid=1" as select * from actor // or alter an existing virtual table alter virtualtable vt_actors primarykey "actor_id" // keyfieldlist and primarykey are synonymous alter virtualtable vt_actors keyfieldlist "actor_id"
Lianja Web Virtual Tables Demo
The Lianja App Builder distribution includes the sample App 'Lianja Web Virtual Tables Demo' (example_webvirtualtables).
This App uses virtual tables to access a MySQL table from the sakila database and a MS SQL Server table from the AdventureWorks database. To run the App, you will need ODBC access to a MySQL Server with the sakila sample database and to the AdventureWorks sample database on MS SQL Server.
The Lianja database for the App is called cloudlibtest and it has 2 virtual tables.
The first is vt_actors, a virtual table for the actor table in the MySQL sakila database.
To use this virtual table, you first need to create a 32-bit ODBC DSN called lianja_mysqltest to connect to the MySQL sakila database (Configuring a Connector/ODBC DSN on Windows).
Note: If you want to use a DSN with a different name, you need to change the ODBC Connection value for the vt_actors virtual table.
The second is vt_customers, a virtual table for the Sales.Customer table in the MS SQL Server AdventureWorks database.
To use this virtual table, you first need to create a 32-bit ODBC DSN called lianja_mssqltest to connect to the MS SQL Server AdventureWorks database (help information is displayed in the ODBC Data Source Administrator or can be found here).
Note: If you want to use a DSN with a different name, you need to change the ODBC Connection value for the vt_customers virtual table.
If you change any values in the cloudlibtest virtual tables, make sure you Deploy the database before running the example_webvirtualtables App in the Lianja Web Client in your browser.
And don't forget to open example_webvirtualtables in the Web App View and Deploy the App.
More on Virtual Table Properties
Coming soon ...