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Store Date and Time in Oracle Date Column

I am migrating a DB2 table to an Oracle database using JPA and JEE. Because of this, I'm having problems with the "Date" and "Time" type columns. More specifically, in Oracle there is no data type "Time", so I'm trying to store from DB2 the concatenation of 2 columns (one of type Date and another of type Time) inside a column of type "Date" of the Oracle database. This way, I show you how I defined the column in the Oracle database and the mapping I defined:
, DATA_HORA_CREACIO DATE DEFAULT
TO_DATE('0001-01-01-00.00.00','YYYY-MM-DD-HH24.MI.SS')
NOT NULL
private Date dataHoraCreacio;
#Temporal(TemporalType.TIMESTAMP)
#Column(name = "DATA_HORA_CREACIO", nullable = false)
public Date getDataHoraCreacio() {
return this.dataHoraCreacio;
}
public void setDataHoraCreacio(Date dataHoraCreacio) {
this.dataHoraCreacio = dataHoraCreacio;
}
SimpleDateFormat sdfDateHour = new SimpleDateFormat("yyyy-MM-dd-HH.mm.ss");
String data = sdfDate.format(comandaAvariaDb2.getId().getDataCreacio());
String hora = sdfHour.format(comandaAvariaDb2.getId().getHoraCreacio());
comandaAvariaOraId.setDataHoraCreacio(sdfDateHour.parse(data + "-" + hora));
Even so, although the work variable that covered the information is correctly informed, the part referring to the time is stored and not inserted in the database:
Variable working data: Thu Feb 02 18:42:53 CET 2006
DataBase inserted Value: 2006-02-02
I've been trying things out for several hours without making it work. Even so, if I have managed to work with a column of type "Timestamp" but I do not think the best solution because the milliseconds occupy an unnecessary space.
Any ideas?
Thanks in advance.

If you use an Oracle DATE value for DATA_HORA_CREACIO, you should be able to directly insert timestamps from DB2. It's just that selecting a DATE column without any hints for output will give you only the date-part in display:
CREATE TABLE STACK2
(DATA_HORA_CREACIO DATE
DEFAULT TO_DATE('0001-01-01-00.00.00',
'YYYY-MM-DD-HH24.MI.SS') NOT NULL);
INSERT INTO STACK2 VALUES
(TO_DATE('2017-05-30-16.47.32','YYYY-MM-DD-HH24.MI.SS'));
SELECT DATA_HORA_CREACIO,
TO_CHAR(DATA_HORA_CREACIO, 'YYYY-MM-DD'),
TO_CHAR(DATA_HORA_CREACIO, 'HH24:MI:SS') FROM STACK2;
Result is:
See this extract from Oracle DATE definition:
DATE Datatype
The DATE datatype stores date and time information.
Although date and time information can be represented in both
character and number datatypes, the DATE datatype has special
associated properties. For each DATE value, Oracle stores the
following information: century, year, month, date, hour, minute, and
second.

Retrieving UTC DATETIME field from MySQL in Java when server timezone is not UTC

I'm trying to write code to interoperate with a third-party-developed database using Java and MySQL. This database has a field that stores a time stamp in a DATETIME field as a UTC date. The timezone for the server on which both the database and client run is set to a non-UTC zone (Europe/London), so by default the timestamp is read back incorrectly as if it were a local time. I'm trying to write code to read it back as UTC.
I have read several similar questions here, but none of them have an answer that works for me:
MySQL - how to store time with correct timezone? (from Java)
How to store a java.util.Date into a MySQL timestamp field in the UTC/GMT timezone?
Date in UTC in mysql
How do I set the time zone of MySQL?
Unfortunately, I cannot change any server settings, so I have tried using the connection's "time_zone" variable to set the database server to use UTC and the optional Calendar parameter to ResultSet.getTimestamp to retrieve the date, but this has no effect on the result. Here is my code:
private static final Calendar UTCCALENDAR = Calendar.getInstance (TimeZone.getTimeZone (ZoneOffset.UTC));
public Date getDate ()
{
try (Connection c = dataSource.getConnection ();
PreparedStatement s = c
.prepareStatement ("select datefield from dbmail_datefield where physmessage_id=?"))
{
fixTimeZone (c);
s.setLong (1, getPhysId ());
try (ResultSet rs = s.executeQuery ())
{
if (!rs.next ()) return null;
return new Date (rs.getTimestamp(1,UTCCALENDAR).getTime ()); // do not use SQL timestamp object, as it fucks up comparisons!
}
}
catch (SQLException e)
{
throw new MailAccessException ("Error accessing dbmail database", e);
}
}
private void fixTimeZone (Connection c)
{
try (Statement s = c.createStatement ())
{
s.executeUpdate ("set time_zone='+00:00'");
}
catch (SQLException e)
{
throw new MailAccessException ("Unable to set SQL connection time zone to UTC", e);
}
}
The database field I'm trying to read has a value stored in it as follows:
mysql> select * from dbmail_datefield where physmessage_id=494539;
+----------------+--------+---------------------+
| physmessage_id | id | datefield |
+----------------+--------+---------------------+
| 494539 | 494520 | 2015-04-16 10:30:30 |
+----------------+--------+---------------------+
But unfortunately, the result comes out as BST not UTC:
java.lang.AssertionError: expected:<Thu Apr 16 11:30:30 BST 2015> but was:<Thu Apr 16 10:30:30 BST 2015>

Your client getDate() code looks correct as far as it goes. I think you also need to get the MySQL Connector/J JDBC driver to treat the dates stored in the table as UTC dates, to avoid a spurious time zone conversion. This means setting the effective server time zone, in addition to the client session time zone and Calendar used for JDBC getTimestamp calls as you're doing.
Take a look at the values you got in your failed assertion, and which direction the error is in:
expected:<Thu Apr 16 11:30:30 BST 2015> but was:<Thu Apr 16 10:30:30 BST 2015>
What you got back was 10:30 BST, which is 9:30 GMT. This is consistent with the database treating that 10:30 in the table as a BST value and spuriously converting it to GMT for you, before you parse it as a GMT date. That's the opposite direction of a GMT value being spuriously converted to BST.
This may be a JDBC-specific issue, because JDBC requires that time times be converted to the local zone. (Where the MySQL C API doesn't, probably because C's classic time types are not zone-aware the way Java's are.) And it needs to know what zone it's converting from, as well. The MySQL TIMESTAMP type is always stored as UTC. But that's not stated for the DATETIME type. I think that implies that MySQL is going to interpret DATETIME column values as being in the server's time zone. Which you mentioned as being set to BST, and that's consistent with the direction of the shift shown in your assertion error message.
The time_zone session variable you set is telling the MySQL server what your client machine's time zone is, but it doesn't affect what the server thinks its own time zone is. That can be overridden with the serverTimezone JDBC connection property. On your connection, set the serverTimezone to UTC, and make sure useLegacyDatetimeCode is off. (And look through the other zone-related properties if that doesn't work.) See if that gets your dates to come through as UTC with the same calendar field values as in the database.
Be aware that this is going to change the interpretation of other DATETIME values in your database: they're all going to look like UTC dates now (in the context of your JDBC connection). Whether that's correct is going to depend on how they were populated initially. While your client code will have the behavior you want, I don't know if this system as a whole can be made to behave fully consistently without setting the server's time zone to UTC at the server level. Basically, if it doesn't have its zone set to UTC, it's not fully configured for the behavior you want, and you're kludging around it.

Maybe you can use JodaTime as follows;
private static final Calendar UTCCALENDAR = Calendar.getInstance (TimeZone.getTimeZone (ZoneOffset .UTC));
public Date getDate ()
{
try (Connection c = dataSource.getConnection ();
PreparedStatement s = c
.prepareStatement ("select datefield from dbmail_datefield where physmessage_id=?"))
{
s.setLong (1, getPhysId ());
try (ResultSet rs = s.executeQuery ())
{
if (!rs.next ()) return null;
DateTime dt = new LocalDateTime(rs.getTimestamp(1,UTCCALENDAR).getTime ()).toDateTime(DateTimeZone.forID("Europe/London"));
return dt.toDate(); }
}
catch (SQLException e)
{
throw new MailAccessException ("Error accessing dbmail database", e);
}
}
EDIT:
java.util.Date is not TimeZone agnostic. The method toDateTime takes care of TimeZone and DST so you don't care about it
The following code:
public static void main(String[] args) {
// 29/March/2015 1:05 UTC
DateTime now = new DateTime(2015, 3,29,1,5,DateTimeZone.UTC);
// Pre DST 29/March/2015 0:30 UTC
DateTime preDst = new DateTime(2015, 3,29,0,30,DateTimeZone.UTC);
System.out.println("1:05 UTC:"+now);
System.out.println("0:30 UTC:"+preDst);
DateTimeZone europeDTZ = DateTimeZone.forID("Europe/London");
DateTime europeLondon = now.toDateTime(europeDTZ);
System.out.println("1:05 UTC as Europe/London:"+europeLondon);
DateTime europeLondonPreDst = preDst.toDateTime(europeDTZ);
System.out.println("0:30 UTC as Europe/London:"+europeLondonPreDst);
}
Will print:
1:05 UTC:2015-03-29T01:05:00.000Z
0:30 UTC:2015-03-29T00:30:00.000Z
1:05 UTC as Europe/London:2015-03-29T02:05:00.000+01:00
0:30 UTC as Europe/London:2015-03-29T00:30:00.000Z
If you can see JodaTime takes care of DST.

Your best bet, in my view, is to tell MySQL to use GMT and handle all local time issues in your application code, not your database. The values in the database would always be GMT, full stop, which is unambiguous. As you say, with daylight savings time (summer time) adjustments, you can end up with the same value in your database for what is, to us humans, two different times.
This also makes the database portable. If you move to North America and start using MySQL set to (say) Central time, all of a sudden the values in your database seem to have moved several hours. I had that issue with a database I inherited which was using the server's local time, when I moved it from the east coast of the U.S. to the west coast, not having thought to check whether MySQL was slaved to the machine's zone...
long t = 1351382400000; // the timestamp in UTC
String insert = "INSERT INTO my_table (timestamp) VALUES (?)";
PreparedStatement stmt = db.prepareStatement(insert);
java.sql.Timestamp date = new Timestamp(t);
stmt.setTimestamp(1, date);
stmt.executeUpdate();
.....
TimeZone timezone = TimeZone.getTimeZone("MyTimeZoneId");
Calendar cal = java.util.Calendar.getInstance(timezone);
String select = "SELECT timestamp FROM my_table";
// some code omitted....
ResultSet rs = stmt.executeQuery();
while (rs.next()) {
java.sql.Timestamp ts = rs.getTimestamp(1);
cal.setTimeInMillis(ts.getTime());
System.out.println("date in db: " + cal.getTime());
}

If you want to use timezone you can read column as UTC.
ZonedDateTime zdt = ZonedDateTime.of(rs.getTimestamp(1).toLocalDateTime(), ZoneOffset.UTC);
Next you can change to whatever timezone you want using:
zdt = zdt.withZoneSameInstant(ZoneId.of(
TARGET_ZONE));
If you want only to read Date and do not care about zones at all use only:
LocalDateTime ldt = rs.getTimestamp(1).toLocalDateTime()
You will obtain LocalDateTime without timezone.
If you have to return java.util.Date use:
Date.from(ldt.atZone(ZoneOffset.UTC).toInstant());

Don't think about converting or adapting time zone. Don't think about the TZ the mysql uses to store your timestamps or anythink like that. Those things are already handled.
There are three things that you must handle: INPUT, OUTPUT and bugs.
INPUT
When a user enters a date (in a form) without an explicit time zone you have to know what TZ did he intend to use. You can use a SimpleDateFormat object with time zone set to solve this. You don't have to convert the input date, you have to 'interpret' it correctly. Once you have a correctly interpreted Date or timestamp you are done with input.
Input is not only user input, includes configuration files too.
OUTPUT
The same here. Forget about what TZ have your Date objects and timestamps have none, they are just milliseconds since epoch. You have to format your dates to the TZ the user expects so he understand them.
Bugs
You may have bugs in your code related to TZ, but libraries may have them too!!
I noticed mysql java driver failed to communicate the client timezone to the server.
This command s.executeUpdate ("set time_zone='+xx:yy'"); is the workaround but you are using it wrong. You have to tell the server with it the TZ the client is using, before both inserting and querying. The variable is stored in the session. Maybe you may automatize it on your connection pool config.
This is needed so the server know what TZ the client need to use to read or write. This is not dependent on server TZ. It does not mean "store this date in UTC", it does mean "this date I am giving to you is UTC" and "Send me result sets in UTC". No matter you are using Date class with it's internal TZ, the driver screws it up, you would need to set that session variable.
By default it assumes client TZ is the same as server TZ so you shouldn't need to worry about it as you said they are the same.

java to format date and to return it as date object

I have a pojo class in which one of the field is date. Here I am using hibernate to insert values into the db using these pojos.
I have set the current date value for this property and I am inserting the value to the DB. Here I need to generate the insert script programaticaly. I have done this and i am printing the insert statement in the console. But while printing in the console the date is shown as Fri Jun 07 04:49:07 ACT 2013 and the insert statement is
INSERT INTO tables (dates)values('Fri Jun 07 04:49:07 ACT 2013');
I don't want to generate the script like this i need it as
INSERT INTO tables (dates)values('2013-06-07');
I know We can use simple date formatter but i need this as date to set the POJO value. So if it is String it will not be set into the object.
I am forming the query as below
StringBuffer columnName = new StringBuffer();
columnName.append("insert into Tables values ('"+obj.getdates()+"')");
Before i used logger and at that time the query was formed and i think hibernate took care of that formatting because after inserting the query was formed as
INSERT INTO tables (dates)values('2013-06-07');
But now by hardcoding it is giving the above query whcih is not getting executed as the date value is not correct.
Can anyone help me here. Also in the case of hibernate whether formatting is done by hibernate or at the backend whether it is converting automatically
Thanks

convert your date into java.sql.Date
java.util.Date utilDate = new java.util.Date();
java.sql.Date sqlDate = new java.sql.Date(utilDate.getTime());
System.out.println("utilDate:" + utilDate);
System.out.println("sqlDate:" + sqlDate);

Java: Insert into a table datetime data

I am trying to insert into a variable in MS- SQL database the current date and the time.
I use this format:
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
Calendar cal = Calendar.getInstance();
System.out.println(dateFormat.format(cal.getTime()));
and I get this as a result 2013-01-28 09:29:37.941
My field in the database is defined datetime and as I have seen in other tables which have the same field, the date and the time is written exactly like this 2011-07-05 14:18:33.000.
I try to insert into the database with a query that I do inside a java program, but I get this error
SQL Exception: State : S0003 Message: The conversion of a varchar
data type to a datetime data type of the value is out of range. Error
: 242
My query is like that:
query = "INSERT INTO Companies CreatedOn"+
"VALUES ('" + dateFormat.format(cal.getTime()) + "')"
but I don't understand what I am doing wrong.

According to the error description, you are inserting an incorrect type into the database. See JDBC to MSSQL. You should convert Calendar to Timestamp.
Try using:
PrepareStatement statement
= connection.prepareStatement("INSERT INTO Companies CreatedOn VALUES(?)");
java.sql.Timestamp timestamp = new java.sql.Timestamp(cal.getTimeInMillis());
statement.setTimestamp(1, timstamp);
int insertedRecordsCount = statement.executeUpdate();

First of all, do NOT use string concatenation. Have you ever heart about SQL injection?
Correct way how to do that is to use prepared statement:
Idea is you define statement with placeholders and than you define value for those placeholders.
See #Taky's answer for more details.

dateFormat#format this method returns formatted string not Date object. Database field is DateTime and it is expecting java.sql.Timestamp to be inserted there not String according to docs.
To conform with the definition of SQL DATE, the millisecond values
wrapped by a java.sql.Date instance must be 'normalized' by setting
the hours, minutes, seconds, and milliseconds to zero in the
particular time zone with which the instance is associated.
Try java.sql.Timestamp object instead of String in query and I'd recommend you to use PreparedStatement.

This is because you are trying to save String date value to Date type DB field.
convert it to Data dataType
You can also use the datetime "unseparated" format yyyymmdd hh:mm:ss

You could use Joda framework to work with date/time.
It maps own date/time types to Hibernate/SQL types without problem.
When you set parameters in HQL query joda carries about right type mapping.

If you want to store current date and time then you should use MYSQL inbuilt method NOW().
for brief documentation refer http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html . so your code will be like.
INSERT INTO Companies CreatedOn VALUES(NOW())"
However If you want to do it using java Date-util then it should be
Calendar cal = Calendar.getInstance();
java.sql.Timestamp timestamp = new Timestamp(cal.getTimeInMillis());

mapping dates in hibernate and mysql

We have an app in which we are using hibernate with mysql db.
We have a db script import.sql which have some insert into statements and we also have some date fields in db like start_date end_date in which we are string dates in default format, that is,YYYY-MM-DD.
Now issue is at the time of retrieving/comparing dates hibernates showing strange behaviour for example suppose if we have a date 2012-01-30 then hibernate reads in proper format that is, Jan 30 2012, but if we have a date like 2012-02-06 then hibernate reads as June 02 2012. my DAO for comparing and retrieving result is as follows
public final List<Record> getPastRecords(final java.util.Date currentDate) {
List<Record> pastRecord = session.createCriteria(Record.class)
.add(Restrictions.lt("endTime", currentDate))
.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY).list();
return pastRecord;
}
Any idea what I am doing wrong?

without detailed code explanation guessing what may be the problem is very hard through i guess
it may be because of java.util.Date try to use java.sql.Date as when you call methods/constructors of libraries that deal with database better to use wrapper of java.util.Date which is java.sql.Date.
refer http://www.theresearchkitchen.com/archives/58