TO_VECTOR

TO_VECTOR is a constructor that takes a string of type VARCHAR2, CLOB, BLOB, or JSON as input, converts it to a vector, and returns a vector as output. TO_VECTOR also takes another vector as input, adjusts its format, and returns the adjusted vector as output. TO_VECTOR is synonymous with VECTOR.

Syntax

Description of the illustration to_vector_vecse.eps

Parameters

• expr must evaluate to one of:

  • A string (of character types or CLOB) that represents a vector.
  • A VECTOR.
  • A BLOB. The BLOB must represent the vector's binary bytes.
  • A JSON array. All elements in the array must be numeric.

  If expr is NULL, the result is NULL.

  The string representation of the vector must be in the form of an array of non-null numbers enclosed with a bracket and separated by commas, such as [1, 3.4, -05.60, 3e+4]. TO_VECTOR converts a valid string representation of a vector to a vector in the format specified. If no format is specified the default format is used.

• number_of_dimensions must be a numeric value that describes the number of dimensions of the vector to construct. The number of dimensions may also be specified as an asterisk (*), in which case the dimension is determined by expr.

• format must be one of the following tokens: INT8, FLOAT32, FLOAT64, BINARY, or *. This is the target internal storage format of the vector. If * is used, the format will be FLOAT32.

  Note that this behavior is different from declaring a vector column. When you declare a column of type VECTOR(3, *), then all inserted vectors will be stored as is without a change in format.

• storage_format must be one of the following tokens: DENSE, SPARSE, or *. If no storage format is specified or if * is used, the following will be observed depending on the input type:

  • Textual input: the storage format will default to DENSE.
  • JSON input: the storage format will default to DENSE.
  • VECTOR input: there is no default and the storage format is not changed.
  • BLOB input: there is no default and the storage format is not changed.

Examples

SELECT TO_VECTOR('[34.6, 77.8]');

TO_VECTOR('[34.6,77.8]')
---------------------------------------------------------
[3.45999985E+001,7.78000031E+001]



SELECT TO_VECTOR('[34.6, 77.8]', 2, FLOAT32);

TO_VECTOR('[34.6,77.8]',2,FLOAT32)
---------------------------------------------------------
[3.45999985E+001,7.78000031E+001]



SELECT TO_VECTOR('[34.6, 77.8, -89.34]', 3, FLOAT32);

TO_VECTOR('[34.6,77.8,-89.34]',3,FLOAT32)
-----------------------------------------------------------
[3.45999985E+001,7.78000031E+001,-8.93399963E+001]



SELECT TO_VECTOR('[34.6, 77.8, -89.34]', 3, FLOAT32, DENSE);

TO_VECTOR('[34.6,77.8,-89.34]',3,FLOAT32,DENSE)
---------------------------------------------------------------------
[3.45999985E+001,7.78000031E+001,-8.93399963E+001]

Note:

• For applications using Oracle Client libraries prior to 23ai connected to Oracle Database 23ai, use the TO_VECTOR function to insert vector data. For example:

  INSERT INTO vecTab VALUES(TO_VECTOR('[1.1, 2.9, 3.14]'));

• Applications using Oracle Client 23ai libraries or Thin mode drivers can insert vector data directly as a string or a CLOB. For example:

  INSERT INTO vecTab VALUES ('[1.1, 2.9, 3.14]');