1. A method for migrating tables in databases, comprising: calculating a first migration factor for a first table in a source database using a first write density factor for the first table; calculating a second migration factor for a second table in the source database using a second write density factor for the second table; calculating a third migration factor for a third table in the source database using a third write density factor for the third table; selecting the first table based on a first determination that the first migration factor is greater than the second migration factor and the third migration factor, wherein the first write density factor is greater than the second write density factor and the third write density factor; migrating, based on the first determination, the first table to a target database; and after migration of the first table: calculating a second updated migration factor for the second table using the second write density factor and a first source/target joins factor for the second table, wherein the first source/target joins factor takes into account that the first table has been migrated to the target database; calculating a third updated migration factor for the third table using the third write density factor and a second source/target joins factor for the second table; selecting the second table based on a second determination that the second updated migration factor is greater than the third updated migration factor, wherein the first source/target joins factor is greater than the second source/target joins factor; and migrating, based on the second determination, the second table to the target database.