将BLOB与Oracle数据库中的其他BLOB进行比较 [英] Compare BLOB against other BLOBs in Oracle database

问题描述

如何检查数据库中是否存在blob的重复项.我的数据库中有文档表，但是我不确定如何检查其中一个是否重复.我知道您应该使用dbms_lob.compare函数，但是在阅读了有关该主题的一些线程和文章之后，我仍然不明白这一点.

How to check if there is a duplicate of a blob in a database. I have documents table in the database, however I'm not sure how to check if one of them has a duplicate. I know you're supposed to use dbms_lob.compare function but after reading a few threads and articles on the topic I still do not understand this.

Documents表具有document_id列和data(blob)列.我怎么可能检查document_id = 1是否重复?

Documents table has document_id column and and data(blob) column. How can I possibly check if document_id = 1 has a duplicate?

推荐答案

查看其他类似的答案，

See other similar answers, like this one. "If dbms_lob.compare(lob1, lob2) = 0, they are identical."

select *
from documents dup
join documents orig on orig.document_id = 1
    and dup.document_id <> orig.document_id
where dbms_lob.compare(orig.blob, dup.blob) = 0;

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