Duplicated 'birthNumber' entries in DB

[veny]

try following to see the problem:
select count(surname) as CNT, birthNumber from customer group by birthNumber order by CNT desc

[veny]

found following entries in one unit:

orientdb {smevente}> select from customer where birthNumber = '525423193' 

----+--------+-----+-----+------+-------+-------+--------+--------+--------+---------+---------+---------+---------+---------+---------+---------+---------
#   |@RID    |city |unit |degree|zipCode|careers|revision|surname |employer|firstname|deletedBy|birthNumb|phoneNumb|street   |sendingCh|asciiFull|deletedAt
----+--------+-----+-----+------+-------+-------+--------+--------+--------+---------+---------+---------+---------+---------+---------+---------+---------
0   |#15:1043|Plzeň|#13:0|null  |31200  |null   |0       |Hrdinová|null    |Jindřiška|null     |525423193|721231620|Družby 17|1        |JINDRI...|null     
1   |#15:1318|Plzeň|#13:0|null  |32300  |null   |0       |Hrdinová|null    |Jindřiška|<X>      |525423193|721231620|Toužim...|1        |JINDRI...|2000-0...
----+--------+-----+-----+------+-------+-------+--------+--------+--------+---------+---------+---------+---------+---------+---------+---------+---------

2 item(s) found. Query executed in 0.033 sec(s).
orientdb {smevente}> select from customer where birthNumber = '5459060519'

----+--------+-----+-----+------+-------+-------+-------+--------+--------+---------+----------+----------+----------+-------------+---------------
#   |@RID    |city |unit |degree|surname|zipCode|careers|revision|employer|firstname|birthNumbe|phoneNumbe|street    |sendingChanne|asciiFullname  
----+--------+-----+-----+------+-------+-------+-------+--------+--------+---------+----------+----------+----------+-------------+---------------
0   |#15:1067|Plzeň|#13:0|null  |Šobrová|32300  |null   |0       |null    |Jindřiška|5459060519|721048822 |Brněnsk...|1            |JINDRISKA SO...
1   |#15:1329|Plzeň|#13:0|null  |Šobrová|32300  |null   |0       |null    |Jindřiška|5459060519|721048822 |Brněnsk...|1            |JINDRISKA SO...
----+--------+-----+-----+------+-------+-------+-------+--------+--------+---------+----------+----------+----------+-------------+---------------

2 item(s) found. Query executed in 0.028 sec(s).
orientdb {smevente}> select from customer where birthNumber = '6259211530'

----+--------+-----+------+-------+-------+--------+--------+---------+---------+---------+---------+----------+-----------+-----------+-----------
#   |@RID    |unit |degree|zipCode|careers|revision|employer|firstname|surname  |birthNumb|phoneNumb|street    |sendingChan|city       |asciiFullna
----+--------+-----+------+-------+-------+--------+--------+---------+---------+---------+---------+----------+-----------+-----------+-----------
0   |#15:1115|#13:0|null  |35301  |null   |0       |null    |Sylva    |Bandasová|625921...|605222121|Husova ...|1          |Mariánsk...|SYLVA BA...
1   |#15:1315|#13:0|null  |35301  |null   |0       |null    |Sylva    |Bandasová|625921...|605222121|Husova 539|1          |Mariánsk...|SYLVA BA...
----+--------+-----+------+-------+-------+--------+--------+---------+---------+---------+---------+----------+-----------+-----------+-----------

2 item(s) found. Query executed in 0.027 sec(s).
orientdb {smevente}> select from customer where birthNumber = '7053282104'

----+--------+-----+------+------+-------+-------+--------+--------+---------+---------+---------+---------+----------+-------------+--------------
#   |@RID    |unit |degree|city  |zipCode|careers|revision|employer|firstname|birthNumb|phoneNumb|surname  |sendingCha|street       |asciiFullname 
----+--------+-----+------+------+-------+-------+--------+--------+---------+---------+---------+---------+----------+-------------+--------------
0   |#15:1712|#13:0|null  |Tlučná|33026  |null   |0       |null    |Petra    |705328...|737103563|Janouš...|1         |Ke koupali...|PETRA JANOU...
1   |#15:1716|#13:0|null  |Tlučná|33026  |null   |0       |null    |Petra    |705328...|737103563|Janouš...|1         |Ke koupali...|PETRA JANOU...
----+--------+-----+------+------+-------+-------+--------+--------+---------+---------+---------+---------+----------+-------------+--------------

2 item(s) found. Query executed in 0.185 sec(s).