6.3.1.2 Return Value of SQL Table Functions

The Oracle Machine Learning for R SQL table functions return a table.

The structure and contents of the table are determined by the results of the R function passed to the SQL table function and by the OUT_QRY parameter. The R function can return a data.frame object, other R objects, and graphics. The structure of the table that represents the results of the R function is specified by one of the following OUT_QRY values:

• NULL, which results in a table that has a serialized object that can contain both data and image objects.

• A table signature specified in a SELECT statement, which results in a table that has the defined structure. The result of the R function must be a data.frame. No images are returned.

• The string 'XML', which results in a table that has a CLOB that can contain both structured data and graph images in an XML string. The non-image R objects, such as data.frame or model objects, are provided first, followed by the base 64 encoding of a PNG representation of the image.

• The string 'PNG', which results in a table that has a BLOB that contains graph images in PNG format. The table has the column names name, id, and image.