Valentina database allows you to compress data stored into a BLOB value easily. To this end it is enough to specify the fCompression flag for a BLOB field. When this flag is ON Valentina engine does automatic compression/decompression of a BLOB value.
You may wonder, why have this inside of database engine? You can self implement compression before/after save/load of a BLOB value. But actually that is not so easy.
The main advantage from such compression you get with e.g. VTEXT field (sub-class of VBLOB). This field can be indexed. Now imagine that you have ZIPed text self and save it to the database. How will db engine be able to index it? To be able to do indexing, engine itself should be able to uncompress value, extract words and add them to the index.
Now the question is how big the bonus from this feature is? Well, average compression of ZIP for text is about 7 times. So your, e.g. 7GB text data can go down to 1GB on the disk.