6.2.6 Parameter marker escaping

Prefix literal ?, :name or &name in a command with a backslash. The executor removes the escaping backslash and emits the marker without consuming a parameter.

Literal output	DataQL fragment text	Equivalent Java string
?	\?	"\\?"
:name	\:name	"\\:name"
&name	\&name	"\\&name"

Inside <% ... %>, write one backslash. Scripts embedded in Java strings must also follow Java string escaping.

Specialized data sources require dbVisitor drivers

The specialized data source examples on this page use dbVisitor JDBC drivers. Add the appropriate driver separately and supply its connections through ConnectionProvider:

• Elasticsearch: jdbc-elastic.
• MongoDB: jdbc-mongo.
• Redis: jdbc-redis.
• Milvus: jdbc-milvus.

DataQL parses fragments and binds parameters. Command syntax, supported operations, and JDBC capabilities are defined by each driver's documentation. These examples do not imply support for arbitrary non-relational data sources or automatic conversion of arbitrary SQL into native commands.

Elasticsearch request paths

With the Elasticsearch JDBC adapter, query parameters in the request URL are command text:

var save = @@updateSql(id, name)<%
    PUT /users/_doc/1\?refresh=true\&pretty
    {"id":#{id},"name":#{name}}
%>;
return save(1, 'Alice');

The driver receives:

PUT /users/_doc/1?refresh=true&pretty
{"id":?,"name":?}

Values are [1,"Alice"]; the URL question mark does not consume a binding. This is adapter-native syntax, not a command for a relational database.

JSON colons

Field colons immediately before ? or #{...} need no escaping:

{"id":?,"name":#{name}}

With short named parameters, separate the field colon and parameter colon with whitespace:

{"id": :id,"name": :name}

Markers inside JSON strings remain text. Marker characters inside bound values need no template escaping.

Redis keys and Milvus operators

var save = @@updateSql(name)<%
    HSET user\:1 name #{name}
%>;
return save('Alice');

The Redis driver receives HSET user:1 name ? and ["Alice"].

Escape the literal question mark in Milvus <?> as <\?>:

SELECT * FROM users WHERE id = #{id} ORDER BY text <\?> #{query}

The result is SELECT * FROM users WHERE id = ? ORDER BY text <?> ?. These examples describe parsing; command execution and results depend on the corresponding JDBC adapter.

XML

XML entities are decoded before SQL parsing. Write & for an ampersand and \& for an escaped literal ampersand:

PUT /users/_doc/1\?refresh=true\&pretty
{"id":#{id}}

Inside CDATA, use \&pretty directly. CDATA handles XML syntax only; SQL parameters and rules are still parsed.

Quotes, comments and consecutive backslashes

• Single/double quotes and SQL -- or /* ... */ comments preserve their contents, including backslashes and parameter markers.
• PostgreSQL :: casts are preserved: #{id}::bigint generates ?::bigint.
• Before a parameter marker, an odd number of backslashes uses the final one as an escape. An even number preserves all backslashes and still parses the marker as a parameter.

The table shows fragment source characters:

Input	Parsed text	Binds a parameter
\?	?	No
\\?	\\?	Yes
\\\?	\\?	No

This backslash-removal rule applies to ?, : and &. For fixed strings containing #{...}, ${...} or @{...}, use SQL string literals; do not assume other markers follow the same escape behavior.