4. A method for adding data to a data structure, the method comprising: receiving, by a computer processor, an instruction to insert data into a table of an insert-only in-memory database; adding, by the computer processor, the data to each of an encoding dictionary and a decoding dictionary of the data structure, a first copy of each of the encoding dictionary and the decoding dictionary stored in the main store, and a second copy of each of the encoding dictionary and the decoding dictionary stored in the differential buffer; assigning by the computer processor, a value identifier (valueID) for the added data in each of the encoding and decoding dictionaries, the valueID specifying a location in the table of a corresponding record; and adding, by the computer processor, the valueID into an attribute vector corresponding to the encoding and decoding dictionaries in the data structure, the attribute vector stored in an index; wherein, for each column in the table, there are separate and different encoding dictionaries, decoding dictionaries and attribute vectors.
4. A method for adding data to a data structure, the method comprising: receiving, by a computer processor, an instruction to insert data into a table of an insert-only in-memory database; adding, by the computer processor, the data to each of an encoding dictionary and a decoding dictionary of the data structure, a first copy of each of the encoding dictionary and the decoding dictionary stored in the main store, and a second copy of each of the encoding dictionary and the decoding dictionary stored in the differential buffer; assigning by the computer processor, a value identifier (valueID) for the added data in each of the encoding and decoding dictionaries, the valueID specifying a location in the table of a corresponding record; and adding, by the computer processor, the valueID into an attribute vector corresponding to the encoding and decoding dictionaries in the data structure, the attribute vector stored in an index; wherein, for each column in the table, there are separate and different encoding dictionaries, decoding dictionaries and attribute vectors. 8. The method of claim 4 , wherein the valueID for the added data is added at the bottom of the attribute vector and the attribute vector is not rebuilt.