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What's new for OData support?
 

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What's new for OData support?

This release contains the following new and updated features:
*More efficient text searches using the new ddsearch parameter
*Setting to optimize service behavior for requests using the $top parameter
*Full support for OData write operations
*Changes to the JSON schema format

More efficient text searches using the new ddsearch parameter

Querying to find particular values can be expensive when the search must span many columns and many records. To enable you to improve performance by restricting searches to particular text-based columns, DataDirect Cloud provides a new proprietary query parameter, ddsearch. Using ddsearch instead of OData $filter can improve the results of queries.
To use ddsearch, you configure your schema map to specify which columns to include in the search, and whether to search anywhere or only in the first words. To use the optimized search for Salesforce external objects, you must also configure Salesforce to accept ddsearch as a custom search parameter.
For data sources that support indices for text-based fields, the ddsearch parameter allows you to take advantage of full text searches using an index. Indices allow the underlying database to complete a search more efficiently and reduce the overall load that queries create. Full text search using indices is available for the following data source types:
*DB2 on Linux, UNIX, and Windows — Each column to be searched must have a separate full text index, the full text services must be running, and the database must be enabled for full text. See the DB2 documentation for more information.
*Oracle — Each column to be searched must have a separate full text index, the full text services must be running, and the database must be enabled for full text. See the Oracle documentation for more information.
*Microsoft SQL Server — Each column to be searched must have a separate full text index and the full text index engine must be running. See the Microsoft documentation for more information.
See Configuring an OData schema map and Searching text-based columns for more information.

Setting to optimize service behavior for requests using the $top parameter

Some client applications limit the number of entities in a response with the $top OData parameter, but seldom request the remaining entities from the result set. Other clients frequently use $top and $skip to page through results. The DataDirect Cloud service can optimize response times if you indicate how clients will be using the $top parameter. You can specify the Top Mode in the Data Source definition on the OData tab, as described in Setting OData options. You can also use the ddcloud-top-mode header in a request to inform the DataDirect Cloud OData service of how the client typically uses the $top parameter in queries. The header parameter overrides the Data Source definition value for that request. See Top Mode for information on using the header.

Full support for OData write operations

DataDirect Cloud now has full support for write operations, allowing you to create, update and delete entities using OData. Please note the following:
*The OData Read Only option on the OData tab of a Data Source definition controls write access.
*By default, write operations are enabled (the OData Read Only option is not selected) when you create a new Data Source definition.
*For Data Source definitions created before write operations were available, the OData Read Only option will be selected by default. To enable write operations for an existing OData-enabled Data Source, clear the OData Read Only option and use the Configure Schema editor to regenerate the OData model. Write operations will not work if you fail to regenerate the model. See Configuring an OData schema map for related information about enabling OData access for a data source.

Changes to the JSON schema format

To support efficient searches by excluding unwanted columns, the JSON schema format has changed. Data Source OData schemas created before the March release will continue to work, but to take advantage of the new ddsearch parameter for efficient searches, the schema must define which text-based columns should be exposed to the search and which type of search to use.
See Configuring an OData schema map, JSON schema map syntax and Searching text-based columns for more information.
* Data store types supported for OData use with DataDirect Cloud