# Tools: Merge databases

This tool merges a separate database into the one you are currently working with (the "master"). All records are copied intact—no records are modified or merged. Relations are not modified either.

When merging databases, the database that is being merged loses its original identifiers because they can most often coincide with the identifiers in the one they are merging into. Therefore, the one being merged is automatically completely renumbered - the records receive numbers that are not used in the destination file.

It is a good practice to run the "search duplicates" tool after this one. This is especially important when both databases have information about the same persons.

Attention: Before merging, it is important to save copies of both databases in a separate location - for safety and to be able to roll back if you do not like the result of the merge or there are other problems.

Attention: if one of the files to be merged has not been previously edited in GEDKeeper, but was taken from a third-party source, it is strongly recommended to open it in GEDKeeper and save it under a new name (version), and only then merge. This is necessary because when you first open files from third-party programs and genealogical social networks, the structure of such a file is brought to an optimal form for GEDKeeper.

Attention: the merger is intended for files that do not have a common part. Except for possibly matching few persons. If the merger was performed with files, one of which is a partial modification of the other - there will be a doubling of the common part of persons, which can lead to great difficulties with cleaning and eliminating duplicates, to multiple errors.

See also: Tools: Merge duplicate records.