JSON Data Sources

Virtual DataPort allows using JSON files as data sources.

To define a JSON data source you have to specify the access path to the JSON document (ROUTE clause). The path may include interpolation variables to parameterize the access path depending on the conditions of the query executed at runtime (see more about interpolation variables in the section Execution Context and Interpolation Strings).

To create a JSON data source use the statement CREATE DATASOURCE JSON.

Syntax of the CREATE DATASOURCE JSON statement
CREATE [ OR REPLACE ] DATASOURCE JSON <name:identifier>
    [ FOLDER = <literal> ]
    ROUTE <route> [ <route_filters> ]
    [ IGNORE_ROUTE_ERRORS = { TRUE | FALSE } ]
    [ TRANSFER_RATE_FACTOR = <double> ]
    [ DESCRIPTION = <literal> ]

<route_filters> ::=
  FILTER ( <filter> [, <filter> ]* )

To modify a JSON data source use the statement ALTER DATASOURCE JSON.

Syntax of the ALTER DATASOURCE JSON statement
ALTER DATASOURCE JSON <name:identifier>
    [ ROUTE <route> [ <route_filters> ] ]
    [ IGNORE_ROUTE_ERRORS = { TRUE | FALSE } ]
    [ TRANSFER_RATE_FACTOR = <double> ]
    [ DESCRIPTION = <literal> ]

<route_filters> ::=
  FILTER ( <filter> [, <filter> ]* )

Explanation of some of the parameters of these statements:

  • OR REPLACE: If present and a data source with the same name exists, the current definition is substituted with the new one.
  • IGNORE_ROUTE_ERRORS: Setting this to TRUE is equivalent to selecting the check box Ignore route errors in the configuration of the data source, in the administration tool. The section JSON Sources of the Administration Guide explains how this option works.
  • TRANSFER_RATE_FACTOR: relative measure of the speed of the network connection between the Denodo server and the data source. Use the default value (e.g. 1 for JDBC databases located on premises) if the data source is accessible through a conventional 100 Mbps LAN. Use higher values for faster networks and lower values for data sources accessible through a WAN.