8. A computer program product for executing database queries comprising: a computer readable storage medium having computer readable program code embodied therewith for execution on a processing system, the computer readable program code comprising computer executable instructions configured to be executed by the processing system to: select a column of a first table as a candidate column for creating a dictionary; create tokens for a foreign key in a second table that corresponds to a primary key in the first table, each of the created tokens being a respective compression symbol; generate the dictionary for the selected column using the created tokens as indexes in the dictionary; and modify a query that accesses the column of the first table using a join between the first table and the second table by rewriting the query to eliminate the join by retrieving column values based on using the created tokens for the foreign key in the second table as the indexes into the dictionary to directly obtain from the dictionary one or more values corresponding to one or more column values in the first table.
8. A computer program product for executing database queries comprising: a computer readable storage medium having computer readable program code embodied therewith for execution on a processing system, the computer readable program code comprising computer executable instructions configured to be executed by the processing system to: select a column of a first table as a candidate column for creating a dictionary; create tokens for a foreign key in a second table that corresponds to a primary key in the first table, each of the created tokens being a respective compression symbol; generate the dictionary for the selected column using the created tokens as indexes in the dictionary; and modify a query that accesses the column of the first table using a join between the first table and the second table by rewriting the query to eliminate the join by retrieving column values based on using the created tokens for the foreign key in the second table as the indexes into the dictionary to directly obtain from the dictionary one or more values corresponding to one or more column values in the first table. 13. The computer program product of claim 8 , wherein the dictionary is a multi-column dictionary corresponding to multiple columns in the first table concatenated together.