6.7.4 Streams and Binary Values

DataQL represents binary values with BinaryModel. Uploaded files and application BinaryValue results can bind to binary columns. Query results retain binary semantics and can be passed to a Dataway result handler.

Handler	JDBC types	JDBC operations
bytes.BytesTypeHandler	BINARY, VARBINARY, LONGVARBINARY	setBytes / getBytes
bytes.BlobAsBytesTypeHandler	BLOB	setBlob / getBlob; free the read Blob

The package prefix is net.hasor.dataql.sqlproc.types. BinaryModel defaults to BLOB; jdbcType=VARBINARY selects byte-column handling.

Store an upload

Create this H2 table:

CREATE TABLE attachments (id INT PRIMARY KEY, content BLOB);

Create a Dataway POST API and submit a multipart file named file:

var save = @@insertSql(id, content)<%
    INSERT INTO attachments(id, content)
    VALUES (#{id}, #{content, jdbcType=BLOB})
%>;
return save(1, ${file});

curl -X POST 'http://localhost:8080/api/save-file' \
  -b cookies.txt -F 'file=@hello.txt'

The file binds as BinaryModel and the script returns the affected-row count. Authentication follows application configuration. Store filename and Content-Type in separate columns when required; see Web functions.

Query and download

Create another DataQL API with Raw Value as its result handler:

import 'net.hasor.dataway.function.WebUdfSource' as web;
var find = @@selectSql(id)<%
    SELECT content FROM attachments WHERE id = #{id}
%>;
run web.setHeader('Content-Type', 'application/octet-stream');
run web.setHeader('Content-Disposition', 'attachment; filename=hello.bin');
return find(1);

Default single-row/single-column unwrapping returns the binary value itself. The response contains raw bytes with the chosen headers. For multi-column or multi-row results, select the binary member you want to return.

Application binary values

A UDF can return new BinaryValue(byte[]) or new BinaryValue(inputStream). A plain Java byte array can become a DataQL list; BinaryValue explicitly preserves binary semantics. See the complete UDF setup under binary responses.

Resources and nulls

• Binding reads all bytes from BinaryModel.openStream() and closes that input stream before JDBC execution.
• Reading copies content into memory before ResultSet and Connection close, frees the Blob, and returns an independent BinaryValue.
• SQL NULL returns null; a zero-byte file returns an empty binary value.
• BLOB operations use memory proportional to content size. Upload spilling to disk does not make JDBC BLOB access an end-to-end streaming operation.

There are no standalone InputStream or Reader handlers. Text LOBs become strings and binary streams enter through BinaryModel. Applications can store large files in a file service and keep only their identifiers in SQL.