使用Oracle NBLOB数据存储，再也不用为数据深度分析而烦恼 Oracle NBLOB数据持久存储，如何实现数据深度分析优化？

What is Oracle NBLOB data type?

Oracle NBLOB data type is used to store binary large objects, such as images, audio, video, etc. The N stands for Network, indicating that NBLOB data can be transmitted and accessed over a network.

（Image Source: Unsplash）

How to persist NBLOB data?

1. Define NBLOB field when creating a table

When creating a table, you can define NBLOB field using subtypes of BLOB or CLOB data types.

CREATE TABLE example (
  id NUMBER PRIMARY KEY,
  name VARCHAR2(50),
  image NBLOB
);

2. Insert NBLOB data

When inserting NBLOB data into the table, you can manipulate it using functions from the DBMS_LOB package.

DECLARE
  l_bfile BFILE := BFILENAME('DIRECTORY', 'image.jpg');
  l_blob CLOB;
BEGIN
  DBMS_LOB.OPEN(l_bfile, DBMS_LOB.lob_readonly);
  DBMS_LOB.loadfromfile(l_blob, l_bfile, DBMS_LOB.getlength(l_bfile));
  INSERT INTO example (id, name, image) VALUES (1, 'John Doe', EMPTY_BLOB() || l_blob);
  DBMS_LOB.CLOSE(l_bfile);
END;

3. Query NBLOB data

When querying NBLOB data, you can manipulate it using functions from the DBMS_LOB package.

SELECT id, name, DBMS_LOB.SUBSTR(image, 32767, 1) AS image_part FROM example;

How to use NBLOB data?

1. Retrieve NBLOB data

You can use functions from the DBMS_LOB package to retrieve data from the NBLOB field.

SELECT id, name, DBMS_LOB.SUBSTR(image, 32767, 1) AS image_part FROM example;

2. Update NBLOB data

When updating NBLOB data, you can first delete the value of the NBLOB field, and then insert new NBLOB data.

UPDATE example SET image = EMPTY_BLOB() WHERE id = 1; -- Delete the existing NBLOB data and insert new NBLOB data as shown in the previous insert example.

3. Delete NBLOB data

When deleting NBLOB data, you can simply set the value of the NBLOB field to empty.

UPDATE example SET image = EMPTY_BLOB() WHERE id = 1; -- Delete the existing NBLOB data.

Thank you for reading. Feel free to leave a comment, follow us for more updates, give us a thumbs up, and thank you for watching!

本文链接：https://www.24zzc.com/news/171389265370389.html