The extraction from SAP object to File storage has a lot in common with standard (Glue-2011) SAP table to Storage extraction. The same steps are required in order to execute the extraction. However, there are some differences in the way how the data and metadata are stored on file storage. On this page, we are going to focus on these differences. In order to set up the extraction, you can follow the steps described on page(Glue-2011) SAP table to Storage.
Glue tables on file storage
As in the case of the standard SAP table to Storage scenario, the creation of the Glue table is required before the extraction objects can be created. However, because the storage is file-based, there is no possibility to create a database table-like object in order to store data. Therefore, only metadata in JSON format are stored on the target storage during the Glue table activation, describing the Glue table. The more information about the creation of a Glue table on file storage, please see the page (Glue-2011) Create a Glue table on File storage. You can also find more information about Glue table metadata in the section JSON metadata structure.
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During the extraction process itself, the two types of files are created, These are data files and metadata files for extraction (Glue request). The creation of the files is dependent on the settings defined within File storage options. In the next section, we are going to discuss the particular files and how they can be configured,
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In the default configuration, if extraction reads 0 lines from the source object (e.g. empty delta load), no data file is transferred to the target storage. However, it is possible to customize this behavior using Glue Settings - Binary Storage settings using parameter Generate CSV data file for empty load. If empty data files are enabled, even an empty load will create a data file on target storage, respecting other settings of the Glue table (e.g. Include table header).
Metadata files
Similarly Similar to Glue tables, each extraction to file storage generates a metadata file in JSON format, describing the extraction in technical details.
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The extraction metadata are encapsulated within a single JSON object with a single attribute called “GlueRequest“. This named attribute is a JSON object as well and contains the following information about Glue extraction:
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Also, the generation of the JSON metadata files for empty loads can be switched on/off via Glue Settings - Binary storage settings using parameter Generate JSON metadata file for empty load. If set on (default value = “X“) the JSON metadata will be generated and transferred to target storage even for extraction, that read 0 records from the source object (e.g. empty delta load). If switched off, no metadata will be generated and transferred for such loads.