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One way to shorten a text/varchar column is to use a hash function like MD5, SHA1, or SHA256 to generate a unique hash for each value in the column. The hash can then be stored in a separate column, and duplicates can be eliminated by creating a unique index on the hash column. The original text/varchar column can then be truncated to reduce its length. However, it's important to keep in mind that the use of hash functions can lead to collisions (different values producing the same hash), which can compromise data integrity.