LOB input parameters and LOB outputs for JavaScript Object Notation (JSON) generation functions (for example, JSON_OBJECT, JSON_ARRAY, JSON_OBJECTAGG, and JSON_ARRAYAGG) have known problems and are not supported.

Workaround:

Use VARCHAR parameters instead.

The JavaScript Object Notation (JSON) generation functions (JSON_OBJECT, JSON_ARRAY, JSON_OBJECTAGG, and JSON_ARRAYAGG) can give incorrect JSON output values in a few cases including the following:

• The database character sets are not a UTF8 character set.

• Some of the strings are not be properly escaped.

Workaround:

If possible, limit use of JSON_OBJECTAGG to VARCHAR2 or JSON_ARRAYAGG to VARCHAR2 results and avoid CLOB outputs. Use CLOB outputs only when using single-byte character sets.

To avoid incorrect JSON output from JSON_OBJECTAGG or JSON_ARRAYAGG, escape VARCHAR2 columns using a custom PL/SQL function before passing the results to the operators. The escaping function must escape the double quotation character, the backslash character, and any ASCII control characters or whitespace characters other than the space.

Avoid using JSON_ARRAY or JSON_OBJECT with character sets other than AL32UTF8.

The input to JSON aggregate functions JSON_OBJECTAGG and JSON_ARRAYAGG is limited to 4,000 bytes for each input value. A longer value returns an error message.

Workaround:

None.

SQL condition JSON_EXISTS can now be used with a path expression predicate. However, the path expression predicate cannot contain Unicode escape sequences.

Workaround:

Instead, characters from the database character set (for example, AL32UTF8) can be used. If characters from the database character set are not used, the predicate cannot be evaluated correctly.