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Binary data can be stored in a table using the data type bytea or by using the Large Object feature which stores the binary data in a separate table in a special format and refers to that table by storing a value of type oid in your table. In order to determine which method is appropriate you need to understand the limitations of each method. The bytea data type is not well suited for storing very large amounts of binary data.
While a column of type bytea can hold up to 1 GB of binary data, it would require a huge amount of memory to process such a large value. The Large Object method for storing binary data is better suited to storing very large values, but it has its own limitations.
Specifically deleting a row that contains a Large Object reference does not delete the Large Object. Deleting the Large Object is a separate operation that needs to be performed.
The introduction of this functionality in 7. It is possible to revert the driver back to the old 7. To use the bytea data type you should simply use the getBytes , setBytes , getBinaryStream , or setBinaryStream methods. You can start a transaction block by calling setAutoCommit false.
For example, suppose you have a table containing the file names of images and you also want to store the image in a bytea column: To insert an image, you would use: This also could have been done using the setBytes method if the contents of the image was already in a byte.
Note The length parameter to setBinaryStream must be correct. There is no way to indicate that the stream is of unknown length. If you are in this situation, you must read the stream yourself into temporary storage and determine the length. Now with the correct length you may send the data from temporary storage on to the driver. Retrieving an image is even easier.
We use PreparedStatement here, but the Statement class can equally be used. Here the binary data was retrieved as an byte. You could have used a InputStream object instead. Alternatively you could be storing a very large file and want to use the LargeObject API to store the file: Retrieving the image from the Large Object: Processing Binary Data in JDBC For example, suppose you have a table containing the file names of images and you also want to store the image in a bytea column: