Creating a view allows you to:
- CAST the payload fields to an appropriate data type.
- Rename the header fields using case insensitive naming. Although the example shows the headers in mixed case, you can use whatever case you want in queries.
The examples use a sample river flow data set. To use your own data, replace the table and column names, and authorization object. See Variable Substitutions for Examples for the credentials and location values for the sample data set.
Before proceeding, verify with your database administrator that you have the correct privileges and an authorization object.
- To run NOS-related commands, log on to the database as a user with the required privileges.
- If the foreign table that the new view will represent does not exist, create it or ask your database administrator to create it. See Filtering Using a Path Filter in the CREATE FOREIGN TABLE Definition.
- Create the view on the foreign table:
CREATE VIEW view_name AS ( SELECT columnX, columnY, columnZ, columnN FROM table_name );
Example: Creating a Basic View
Create the view of the foreign table.
If not already done, create the foreign table that the new view will represent. See Filtering Using a Path Filter in the CREATE FOREIGN TABLE Definition.
CREATE VIEW riverflowview AS ( SELECT Flow, GageHeight, Precipitation, Site_no FROM riverflow_pathfilter );
Query the view:
SELECT TOP 2 * FROM riverflowview;
Your result will be similar to the following:
Flow GageHeight Precipitation site_no ------ ---------- ------------- -------------- 17500 10.21 .00 09396100 17700 10.25 .00 09396100
Columns with missing attributes return NULLs when the record does not contain the attribute.