Berkeley DB: Db::set_dup_compare
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# Db::set_dup_compare |

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    #include <db_cxx.h>

    int Db::set_dup_compare(int (*dup_compare_fcn)(const DBT *, const DBT *));

# Description

Set the duplicate data item comparison function.

This comparison function must return an integer less than, equal to, or greater than zero if the first key argument is considered to be respectively less than, equal to, or greater than the second key argument. The same comparison method must be used on a given tree every time it is opened.

The data and size fields of the Dbt are the only fields that may be used for the purposes of this comparison.

The Db::set_dup_compare interface may only be used to configure Berkeley DB before the Db::open interface is called.

The Db::set_dup_compare method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success.

# Errors

EINVAL
  An invalid flag value or parameter was specified.

### Class

Db

# See Also

Db::close, Db::cursor, Db::del, Db::err, Db::fd, Db::get, Db::get_byteswapped, Db::get_type, Db::join, Db::open, Db::put, Db::remove, Db::set_bt_compare, Db::set_bt_minkey, Db::set_bt_prefix, Db::set_cachesize, Db::set_dup_compare, Db::set_errcall, Db::set_errfile, Db::set_errpfx, Db::set_flags, Db::set_h_ffactor, Db::set_h_hash, Db::set_h_nelem, Db::set_lorder, Db::set_malloc, Db::set_pagesize, Db::set_paniccall, Db::set_realloc, Db::set_re_delim, Db::set_re_len, Db::set_re_pad, Db::set_re_source, Db::stat, Db::sync and Db::upgrade.`

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