Custom datasources allow you to interface data services with your own datasource implementation. There are two options for writing a custom datasource, and these two options cover most of the common business use cases: Custom Tabular Data Source or Custom Query Data Source.
Custom tabular datasources: Used to represent data in tables, where a set of named tables contain data rows that can be queried later. A tabular datasource is typically associated with an SQL data services query. This is done by internally using our own SQL parser to execute SQL against the custom datasource. You can use the org.wso2.carbon.dataservices.core.custom.datasource.TabularDataBasedDS interface to implement tabular datasources. For a sample implementation of a tabular custom datasource, see InMemoryDataSource. Also, this is supported in Carbon datasources with the following datasource reader implementation: org.wso2.carbon.dataservices.core.custom.datasource.CustomTabularDataSourceReader.
Custom query datasources: Used when the datasource has some form of a query expression support. Custom query datasources are implemented using the org.wso2.carbon.dataservices.core.custom.datasource.CustomQueryBasedDS interface. You can create any non-tabular datasource using the query-based approach. Even if the target datasource does not have a query expression format, you can create your own. For example, you can support any NoSQL type datasource this way. For a sample implementation of a query-based custom datasource, see EchoDataSource. This is supported in Carbon datasources, with the following datasource reader implementation: org.wso2.carbon.dataservices.core.custom.datasource.CustomQueryDataSourceReader.
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InMemoryDSSample is a sample data service descriptor, which contains a custom tabular datasource as well as a custom query datasource. Also, you can find a sample of a Carbon datasource configuration in |
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