Sensitive data such as personal telephone number, address, social security number at database is prevented to access by SQL search query. In order to prevent security problems it needs to encrypt database. Order preserving encryption (OPE) is a method of encrypting data so that it's possible to make efficient inequality comparisons on the encrypted items without decrypting them. OPE data of database is available to make index without decryption. In this paper, the data preprocessor by reducing plaintext range, the performance of OPE is increased and sensitive data are protected at database.