The difference between blob and clob in oracle

The main differences between BLOB (Binary Large Object) and CLOB (Character Large Object) in Oracle are: 1. BLOB stores binary data, while CLOB stores character data; 2. The maximum size of BLOB is 4 GB, and the maximum size of CLOB is 4 GB or 32 times the database block size; 3. BLOB does not support indexes, while CLOB supports part of the index; 4. Querying BLOB loads the entire BLOB, while querying CLOB only loads the first 4000 characters; 5. BLOB is stored in the LOB segment , and CLOB

The difference between BLOB and CLOB in Oracle

Question: Oracle What is the difference between BLOB and CLOB?

Answer: BLOB (Binary Large Object) and CLOB (Character Large Object) are large objects that store binary files and text files in Oracle database. The main differences between them are as follows:

1. Data type

• BLOB stores binary data such as images, audio or video files.
• CLOB stores character data, such as text files or XML documents.

2. Size Limitations

• The maximum size of a BLOB is 4 GB.
• The maximum size of a CLOB is 4 GB or 32 times the database block size, whichever is smaller.

3. Index

• BLOB does not support indexing.
• CLOB supports a subset of indexes, but only the first 4000 characters.

4. Query efficiency

• When querying a BLOB, Oracle will load the entire BLOB into memory, which may seriously affect performance.
• When querying a CLOB, Oracle only loads the first 4000 characters, which usually does not affect performance.

5. Storage

• BLOBs are stored in specialized segments, called LOB segments.
• CLOBs are stored in tablespaces, along with other table data.

6. Purpose

• BLOB is usually used to store images, videos, audio and binary files.
• CLOBs are commonly used to store text, HTML, XML, and JSON data.

The following is a table summarizing the key differences between BLOBs and CLOBs:

##PurposeBinary fileText file

Features	BLOB	CLOB
Data type	Binary	Character
Size limit	4 GB	4 GB or 32 times the database block size
Index	Not supported	Partially supported
Query efficiency	Low	High
Storage	LOB segment	Table space

The above is the detailed content of The difference between blob and clob in oracle. For more information, please follow other related articles on the PHP Chinese website!