You can write code to filter data returned by requests of your backend application. You'll most likely use these filters to retrieve entities within specific parameters. For example, you might want to get data about users who are "following" a specific other user, businesses in specific geographical locations, and so on.
The following example retrieves a list of restaurants (from a restaurants collection) whose name property contains the value "diner", sorting the list in ascending order by name:
/restaurants?ql=select * where name contains 'diner' order by name asc
Having retrieved the list of restaurants, your code could display the list to your users. You could also use a query to retrieve a list of diners that are located within a particular geographical area (such as near your user's current location).
limitparameter, as discussed in Working with queries.
You query your data by using a query syntax that's like Structured Query Language (SQL), the query language for relational databases. Unlike a relational database, where you specify tables and columns containing the data you want to query, in your queries you specify collections and entities.
The examples in this section illustrate queries using simple strings to make the queries easier to read. You can also use one of the Apigee SDKs, which provide functions through which you can pass query strings, and in some cases shortcuts for bypassing queries altogether.
For more detail about support for queries, see the following topics:
- Querying your data
- Query response values
- Data types supported in queries
- Querying data from the admin portal
- Working with queries
Querying data from the admin portal
The easiest way to try out queries you're considering is to use the admin portal, which you can reach at https://apigee.com/appservices/#!/.
To try out queries in the portal, use the following steps:
- Go to the Data Explorer using the left navigation pane.
- Under Method, select the HTTP method you want to use, as follows:
- GET to retrieve data.
- POST to create data.
- PUT to update data.
- DELETE to delete data.
- In the Path box, enter the path to the collection you're querying.
- In the Query String box, enter your query string.
Note that you put the path and query string in separate fields, rather than appending the query string to the path in the Path box.
The admin portal transforms queries into standard URL-encoded parameters before issuing HTTP requests. For example, given the following query resulting from what you've entered in the portal:
/users?ql=select * where name = 'gladys*'
The string received by Apigee would be the following: