1. A method of tracking modifications to a field in a relational table of a database instance supported by a relational database server, said method comprising: receiving a relational query specifying an update request indicating a new value for said field of said relational table, wherein a present value of said field equals a first value when said relational query is received; storing said first value in said relational table as a historical value of said field; and storing said new value in said field in said relational table as said present value of said field, wherein both of said first value and said new value are stored in said relational table in to receiving said relational query specifying said update request, wherein said new value represents said present value of said field in said relational table after processing of said update request and said first value is also available as said historical value in said relational table after processing of said update request, wherein storing of said first value and said new value in said relational table is enabled by storing two values in said field in said relational table, and wherein said field is enabled to store two values by: receiving instruction indicating said field is of interest for tracking historical values; and in response to receiving said instruction, defining said field as type VARRAY of at least depth 2 causing said field to comprise two sub-columns each sub-column capable of storing a value.