1. A method of using a plurality of (row-identifier, value) pairs to update rows in a table of a database, the method comprising: repeatedly finding, and storing in a structure, a block-identifier of a block that contains a row identified by a row-identifier in at least a group of (row-identifier, value) pairs, by use of a database index; performing a vector read operation, to store in a buffer cache, a number of blocks, said blocks being identified by block-identifiers in the structure; and repeatedly updating, in blocks in the buffer cache, each row identified in the group of (row-identifier, value) pairs, using a corresponding value in the (row-identifier, value) pairs.