sqlQueryBlob

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Module

The sqlQueryBlob accessor is exported by the urn:org:ten60:netkernel:mod:db module. Import this module to gain access to the accessor.

Syntax

URI

active:sqlQueryBlob

Argument	Rules	Description
operand	Mandatory	the <sql> query document
configuration	Optional	optional configuration document

Example Usage

DPML

<instr>
  <type>sqlQueryBlob</type>
  <operand>
    <sql>SELECT blobfield FROM table;</sql>
  </operand>
  <configuration>/myconfiguration/configRDBMS.xml</configuration>
  <target>var:result</target>
</instr>

NetKernel Foundation API

req=context.createSubRequest("active:sqlQueryBlob");
req.addArgument("operand", [resource representation, aspect, or URI] );
result=context.issueSubRequest(req);

Purpose

The sqlQueryBlob accessor performs an SQL query on an RDBMS using a JDBC connection to obtain a Blob in the database as a binary stream. The query is provided in the operand as a canonical <sql> document (see example above). The resulting blob entry is returned as a IAspectReadableBinaryStream. The SQL query must specifically target a single blob field in a database table.

Like the underlying JDBC interface, sqlQueryBlob cannot be used to update a document, use sqlUpdateBlob.

Configuration

By default the configuration will be read from ffcpl:/etc/ConfigRDBMS.xml. The document provides a driver and connection URI (see example below). Alternatively,the configuration can be provided in an optional <configuration> argument - this may be either a URI to a config document or a literal configuration document.

<config>
  <rdbms>
    <jdbcDriver>com.mysql.jdbc.Driver</jdbcDriver>
    <jdbcConnection>
      jdbc:mysql://localhost/mydatabase?user=myusername&amp;password=mypassword
    </jdbcConnection>
  </rdbms>
</config>

For more details on the configuration see the Mod DB Guide