Oracle generates a serial number function

1: Valid time range for smalldatetime on date range 1900/1/1~2079/6/6valid time range for datetime 1753/1/1~9999/ A/ to2: The accuracy of the smalldatetime is only accurate to the point, while the DateTime can be accurate to 3-bit milliseconds. 3: smalldatetime occupies 4 bytes on storage space, and the first 2 bytes store the number of days after base date (January 1, 1900). The second 2 bytes stores the number of minutes after midnight. DateTime occupies 8 bytes, the first 4 bytes store the number of days before or after base date (that is, January 1, 1900), and the last 4 bytes store the number of milliseconds after midnight Oracle generates a serial number functionCREATE OR REPLACE FUNCTIONFn_no_make (V_typeVARCHAR2, V_number_colVARCHAR2, V_table_nameVARCHAR2)/** Parameter Description: * v_type: Encoding prefix * V_NUMBER_COL: The column name of the code * V_table_name: The name of the table in which the code is located*/ RETURN VARCHAR2  isV_old_noVARCHAR2( -);--Original CodeV_old_num Number;--five digit number after the original codeV_new_numVARCHAR2(Ten);--new coded five digit numberV_maked_noVARCHAR2( -);--new CodeV_date_noVARCHAR2( -);--Current date numberV_sqlVARCHAR2(4000);BEGINV_sql:= 'SELECT MAX (' ||V_number_col|| ') from' ||V_table_name; EXECUTEIMMEDIATE V_sql intoV_old_no; V_sql:= 'SELECT SUBSTR (To_char (Sysdate,"'YYMMDD"'), 1, 6) as Date_no from DUAL'; EXECUTEIMMEDIATE V_sql intoV_date_no; V_old_num:=To_number (substr (V_old_no, One,5)); V_new_num:=To_char (V_old_num+ 1);  whileLength (V_new_num)< 5LOOP V_new_num:= '0' ||V_new_num; ENDLOOP; IFV_old_no is NULL ORsubstr (V_old_no,5,6)<>V_date_no ThenV_maked_no:=V_type||V_date_no|| '00001'; ELSEV_maked_no:=V_type||V_date_no||V_new_num; END IF; RETURN(V_MAKED_NO); EXCEPTION whenOTHERS ThenDbms_output.put_line (SQLERRM);ENDFn_no_make;1. Database import, Export command Data export: A. Full export of database test, user Name System Password Manager exported to D:\daochu.dmpExpTest/Test@ORACLE_192.168.28.1 file=D:\daochu.dmp Full=YB. Export the system user in the database with the table of the SYS userExpTest/Test@ORACLE_192.168.28.1  file=D:\DAOCHU.DMP owner=(System,sys) data import: A imports the data from the D:\DAOCHU.DMP into the test database. Imp Dev/Dev@ORACLE_192.168.28.2  file=d:\daochu.dmp Imp Dev/Dev@ORACLE_192.168.28.2  Full=Yfile=file=D:\data\newsmgnt.dmp Ignore=y may have a problem, because some tables already exist, and then it's an error, and the table is not imported. Add Ignore to the back .=y can do it. B Import the table table1 from d:\daochu.dmp to imp Dev/Dev@TEST  file=D:\DAOCHU.DMP tables=(table1)2. Clob,blob Import and Export command in database tablesExpDatabase user Name/Password@ Configuration Name  file=Output file pathLog=Log file path tables=(database table name) query=\ "Query condition \" IMP database user name/Password@ Configuration Name  file=Input file pathLog=Log file path tables=(database table name) ignore=yExpTest/Test@ORACLE_192.168.28.1  file=C + One. DMPLog=C + One.LogTables=(table1) Query=\"whereCreatedBy='sysadmin'   andTo_char (Createtime,'YYYY-MM-DD')='2012-05-17'\ "Imp Dev/Dev@ORACLE_192.168.28.2 file=C + One. DMPLog=C +121.LogTables=(table1) Ignore=y do it with Cmd.exe, the place to note is the query place \ "Execute IMP after exp is executed first

Oracle generates a serial number function