Parameters

General

• Host: contains target IP address or database server hostname.

• Port: contains database server port (8086 by default).

• Database: contains name of the database.

• Retention Policy: contains the retention policy.

• Measurement: contains name of measurement.

Note that if database, retention policy or measurement do not exist in the database server, reading and writing will not be performed

• Items per Request: contains maximum number of items (values) that can be read per one request.

• Query Template: contains query text for data fetch. The information about how the query result is associated with the variables can be found further. Query text can contain the following keywords for replacement:

  • {DATABASE_NAME} - is replaced with the name of database specified in the device.

  • {RETENTION_POLICY_NAME} - is replaced with the name of retention policy specified in the device.

  • {MEASUREMENT_NAME} - is replaced with the name of the measurement specified in the device.

  • {WHERE_CONDITION} - is replaced with WHERE condition: ("tsid" = 'Group1.Series1' AND "tsc" = 'Room_25') OR ("tsid" = 'Group2.Series3' AND "tsc" = 'Room_228'), generated for addresses in the block.

  • {TAG_KEYS} - is replaced with a list of tag keys used in the block, e.g.: "tsid", "tsc", "location"

  • {FIELD_NAMES} - is replaced with a list of fields used in the block, e.g.: "value", "time", "flag"

  • {ITEMS_COUNT} - is replaced with a quantity of unique tags combinations used in the block.

• Inter-request Delay: contains timeout interval (in milliseconds) before the next query is sent.

• Request Timeout - contains time interval (in milliseconds) within which the response from the database server must be received. If the response is not received during the specified interval an error occurs.

Security

• Use Credentials: specifies that it is necessary to use credentials (Base64 Auth in HTTP-header).

• Username: contains the username.

• Password: contains the password.

• Use SSL: specifies that it is necessary to verify database server SSL certificate.

• SSL Verification: contains verification mode of database server SSL certificate:

  • Accept any.

  • Verify chain of trust by using a store of certificates of the operating system.

  • Verify chain of trust by using custom certificate of certification authority.

• Custom CA File: contains custom certificate of certification authority.

Most of the parameters described above are available as OPC UA items. More information about editing server object properties via OPC UA is described here.