Timestamp Class

13.33 Timestamp Class

This class supports the SQL standard TIMESTAMP WITH TIME ZONE and TIMESTAMP WITHOUT TIME ZONE types, and works with all database TIMESTAMP types: TIMESTAMP, TIMESTAMP WITH TIME ZONE, and TIMESTAMP WITH LOCAL TIME ZONE.

Timestamp time components, such as hour, minute, second and fractional section are in the time zone specified for the Timestamp. This is new behavior for the 10g release; previous versions supported GMT values of time components. Time components were only converted to the time zone specified by Timestamp when they were stored in the database. For example, the following Timestamp() call constructs a Timestamp value 13-Nov 2003 17:24:30.0 in timezone +5:30.

Timestamp ts(env, 2003, 11, 13, 17, 24, 30, 0, 5, 30);

The behavior of this call in previous releases would interpret the timestamp components as GMT, resulting in a timestamp value of 13-Nov 2003 11:54:30.0 in timezone +5:30. Users were forced to convert the timestamps to GMT before invoking the constructor. Note that for GMT timezone, both hour and minute equal 0.

This behavior change also applies to setDate() and setTime() methods.

The fields of Timestamp class and their legal ranges are provided in Table 13-49. An SQLException occurs if a parameter is out of range.

Table 13-49 Fields of Timestamp and Their Legal Ranges

Field	Type	Minimum Value	Maximum value
`year`	int	`-4713`	`9999`
`month`	unsigned int	`1`	`12`
`day`	unsigned int	`1`	`31`
`hour`	unsigned int	`0`	`23`
`min`	unsigned int	`0`	`59`
`sec`	unsigned int	`0`	`61`
`tzhour`	int	`-12`	`14`
`tzmin`	int	`-59`	`59`

Table 13-50 Summary of Timestamp Methods

Method	Summary
Timestamp()	`Timestamp` class constructor.
fromText()	Sets the time stamp from the values provided by the string.
getDate()	Gets the date from the `Timestamp` object.
getTime()	Gets the time from the `TimeStamp` object.
getTimeZoneOffset()	Returns the time zone hour and minute offset value.
intervalAdd()	Returns a `Timestamp` object with value (this + interval).
intervalSub()	Returns a `Timestamp` object with value (this - interval).
isNull()	Checks if `Timestamp` is `NULL`.
operator=()	Simple assignment.
operator==()	Checks if a and b are equal.
operator!=()	Checks if a and b are not equal.
operator>()	Checks if a is greater than b.
operator>=()	Checks if a is greater than or equal to b.
operator<()	Checks if a is less than b.
operator<=()	Checks if a is less than or equal to b.
setDate()	Sets the year, month, day components contained for this timestamp.
setNull()	Sets the value of Timestamp to `NULL`
setTime()	Sets the day, hour, minute, second and fractional second components for this timestamp.
setTimeZoneOffset()	Sets the hour and minute offset for time zone.
subDS()	Returns a `IntervalDS` representing this - `val`.
subYM()	Returns a `IntervalYM` representing this - `val`.
toText()	Returns a `string` representation for the timestamp in the format specified.

13.33.1 Timestamp()

Timestamp class constructor.

Syntax	Description
Timestamp( const Environment *env, int year=1, unsigned int month=1, unsigned int day=1, unsigned int hour=0, unsigned int min=0, unsigned int sec=0, unsigned int fs=0, int tzhour=0, int tzmin=0);	Returns a default `Timestamp` object. Time components are understood to be in the specified time zone.
Timestamp();	Returns a `NULL Timestamp` object. A `NULL` timestamp can be initialized by assignment or calling the fromText() method. Methods that can be called on `NULL` timestamp objects are setNull(), isNull() and operator=().
Timestamp( const Environment *env, int year, unsigned int month, unsigned int day, unsigned int hour, unsigned int min, unsigned int sec, unsigned int fs, const string &timezone);	Multibyte support. The timezone can be passed as region, "US/Eastern", or as an offset from GMT, "+05:30". If an empty string is passed, then the time is considered to be in the current session's time zone. Used for constructing values for `TIMESTAMP WITH LOCAL TIME ZONE` types.
Timestamp( const Environment *env, int year, unsigned int month, unsigned int day, unsigned int hour, unsigned int min, unsigned int sec, unsigned int fs, const UString &timezone);	UTF16 (`UString`) support. The timezone can be passed as region, "US/Eastern", or as an offset from GMT, "+05:30". If an empty string is passed, then the time is considered to be in the current session's time zone. Used for constructing values for `TIMESTAMP WITH LOCAL TIME ZONE` types.
Timestamp( const Timestamp &src);	Copy constructor.

Parameter	Description
year	Year component.
month	Month component.
day	Day component.
hour	Hour component.
minute	Minute component.
second	Second component.
fs	Fractional second component.
tzhour	Time zone difference hour component.
tzmin	Timezone difference minute component.
src	The original `Timezone`.

Example 13-11 Using Default Timestamp Constructor

This example demonstrates that the default constructor creates a NULL value, and how you can assign a non-NULL value to a Timestamp and perform operations on it:

Environment *env = Environment::createEnvironment();

//create a null timestamp
Timestamp ts;
if(ts.isNull())
   cout << "\n ts is Null";

//assign a non null value to ts
Timestamp notNullTs(env, 2000, 8, 17, 12, 0, 0, 0, 5, 30);
ts = notNullTs;

//now all operations are valid on ts
int yr;
unsigned int mth, day;
ts.getDate(yr, mth, day);

Example 13-12 Using fromText() method to Initialize a NULL Timestamp Instance

The following code example demonstrates how to use the fromText() method to initialize a NULL timestamp:

Environment *env = Environment::createEnvironment();

Timestamp ts1;
ts1.fromText("01:16:17.12 04/03/1825", "hh:mi:ssxff dd/mm/yyyy", "", env);

Example 13-13 Comparing Timestamps Stored in the Database

The following code example demonstrates how to get the timestamp column from a result set, check whether the timestamp is NULL, get the timestamp value in string format, and determine the difference between 2 timestamps:

Timestamp reft(env, 2001, 1, 1);
ResultSet *rs=stmt->executeQuery(
   "select order_date from orders where customer_id=1");
rs->next();

//retrieve the timestamp column from result set
Timestamp ts=rs->getTimestamp(1);

//check timestamp for null
if(!ts.isNull())
{
   string tsstr=ts.toText(           //get the timestamp value in string format
      "dd/mm/yyyy hh:mi:ss [tzh:tzm]",0);
   if(reft<ts                        //compare timestamps
      IntervalDS ds=reft.subDS(ts);  //get difference between timestamps
}

13.33.2 fromText()

Sets the timestamp value from the string. The string is expected to be in the format specified. If nlsParam is specified, this determines the NLS parameters to be used for the conversion. If nlsParam is not specified, the NLS parameters are picked up from the environment which has been passed. In case environment is not passed, Globalization Support parameters are obtained from the environment associated with the instance, if any.

Sets Timestamp object to value represented by a string or UString.

The value is interpreted based on the fmt and nlsParam parameters. In cases where nlsParam is not passed, the Globalization Support settings of the envp parameter are used.

Syntax	Description
void fromText( const string &timestmpStr, const string &fmt, const string &nlsParam = "", const Environment *env = NULL);	Sets `Timestamp` object to value represented by a `string`.
void fromText( const UString &timestmpStr, const UString &fmt, const UString &nlsParam, const Environment *env = NULL);	Sets `Timestamp` object to value represented by a `UString`; globalization enabled.

Parameter	Description
timestmpStr	The timestamp `string` or `UString` to be converted to a `Timestamp` object.
fmt	The format string.
nlsParam	The NLS parameters string. If `nlsParam` is specified, this determines the NLS parameters to be used for the conversion. If `nlsParam` is not specified, the NLS parameters are picked up from `envp`.
env	The OCCI environment. In globalization enabled version of the method, used to determine `NLS_CALENDAR` for interpreting `timestampStr`. If `env` is not passed, the environment associated with the object controls the setting. Should be a non-`NULL` value if called on a `NULL` `Timestamp` object.

13.33.3 getDate()

Returns the year, month and day values of the Timestamp.

Syntax

void getDate(
   int &year,
   unsigned int &month,
   unsigned int &day) const;

Parameter	Description
year	Year component.
month	Month component.
day	Day component.

13.33.4 getTime()

Returns the hour, minute, second, and fractional second components

Syntax

void getTime(
   unsigned int &hour,
   unsigned int &minute,
   unsigned int &second,
   unsigned int &fs) const;

Parameter	Description
hour	Hour component.
minute	Minute component.
second	Second component.
fs	Fractional second component.

13.33.5 getTimeZoneOffset()

Returns the time zone offset in hours and minutes.

Syntax

void getTimeZoneOffset(
   int &hour,
   int &minute) const;

Parameter	Description
hour	Time zone hour.
minute	Time zone minute.

13.33.6 intervalAdd()

Adds an interval to timestamp.

Syntax	Description
const Timestamp intervalAdd( const IntervalDS& val) const;	Adds an IntervalDS interval to the timestamp.
const Timestamp intervalAdd( const IntervalYM& val) const;	Adds an IntervalYM interval to the timestamp.

Parameter	Description
val	Interval to be added.

13.33.7 intervalSub()

Subtracts an interval from a timestamp and returns the result as a timestamp. Returns a Timestamp with the value of this - val.

Syntax	Description
const Timestamp intervalSub( const IntervalDS& val) const;	Subtracts an `IntervalDS` interval to the timestamp.
const Timestamp intervalsUB( const IntervalYM& val) const;	Subtracts an `IntervalYM` interval to the timestamp.

Parameter	Description
val	Interval to be subtracted.

13.33.8 isNull()

Returns TRUE if Timestamp is NULL or FALSE otherwise.

Syntax

bool isNull() const;

13.33.9 operator=()

Assigns a given timestamp object to this object.

Syntax

Timestamp & operator=(
   const Timestamp &src);

Parameter	Description
src	Value to be assigned.

13.33.10 operator==()

Compares the timestamps specified. If the timestamps are equal, returns TRUE, FALSE otherwise. If either a or b is NULL then FALSE is returned.

Syntax

bool operator==(
   const Timestamp &first,
   const Timestamp &second);

Parameter	Description
first	First timestamp to be compared.
second	Second timestamp to be compared.

13.33.11 operator!=()

Compares the timestamps specified. If the timestamps are not equal then TRUE is returned; otherwise, FALSE is returned. If either timestamp is NULL then FALSE is returned.

Syntax

bool operator!=(
   const Timestamp &first,
   const Timestamp &second);

Parameter	Description
first	First timestamp to be compared.
second	Second timestamp to be compared.

13.33.12 operator>()

Returns TRUE if first is greater than second, FALSE otherwise. If either is NULL then FALSE is returned.

Syntax

bool operator>(
   const Timestamp &first,
   const Timestamp &second);

Parameter	Description
first	First timestamp to be compared.
second	Second timestamp to be compared.

13.33.13 operator>=()

Compares the timestamps specified. If the first timestamp is greater than or equal to the second timestamp then TRUE is returned; otherwise, FALSE is returned. If either timestamp is NULL then FALSE is returned.

Syntax

bool operator>=(
   const Timestamp &first,
   const Timestamp &second);

Parameter	Description
first	First timestamp to be compared.
second	Second timestamp to be compared.

13.33.14 operator<()

Returns TRUE if first is less than second, FALSE otherwise. If either a or b is NULL then FALSE is returned.

Syntax

bool operator<(
   const Timestamp &first,
   const Timestamp &second);

Parameter	Description
first	First timestamp to be compared.
second	Second timestamp to be compared.

13.33.15 operator<=()

Compares the timestamps specified. If the first timestamp is less than or equal to the second timestamp then TRUE is returned; otherwise, FALSE is returned. If either timestamp is NULL then FALSE is returned.

Syntax

bool operator<=(
   const Timestamp &first,
   const Timestamp &second);

Parameter	Description
first	First timestamp to be compared.
second	Second timestamp to be compared.

13.33.16 setDate()

Sets the year, month, day components contained for this timestamp

Syntax

void setDate(
   int year,
   unsigned int month,
   unsigned int day);

Parameter	Description
year	Year component. Valid values are -4713 through 9999.
month	Month component. Valid values are 1 through 12.
day	Day component. Valid values are 1 through 31.

13.33.17 setNull()

Sets the timestamp to NULL.

Syntax

void setNull();

13.33.18 setTime()

Sets the day, hour, minute, second and fractional second components for this timestamp.

Syntax

void setTime(
   unsigned int hour,
   unsigned int minute,
   unsigned int second,
   unsigned int fs);

Parameter	Description
hour	Hour component. Valid values are 0 through 23.
minute	Minute component. Valid values are 0 through 59.
second	Second component. Valid values are 0 through 59.
fs	Fractional second component.

13.33.19 setTimeZoneOffset()

Sets the hour and minute offset for time zone.

Syntax

void setTimeZoneOffset(
   int hour,
   int minute);

Parameter	Description
hour	Time zone hour. Valid values are -12 through 12.
minute	Time zone minute. Valid values are -59 through 59.

13.33.20 subDS()

Computes the difference between this timestamp and the specified timestamp and return the difference as an IntervalDS.

Syntax

const IntervalDS subDS(
   const Timestamp& val) const;

Parameter	Description
val	Timestamp to be subtracted.

13.33.21 subYM()

Computes the difference between timestamp values and return the difference as an IntervalYM.

Syntax

const IntervalYM subYM(
   const Timestamp& val) const;

Parameter	Description
val	`Timestamp` to be subtracted.

13.33.22 toText()

Returns a string or UString representation for the timestamp in the format specified.

If nlsParam is specified, this determines the NLS parameters used for the conversion. If nlsParam is not specified, the NLS parameters are picked up from the environment associated with the instance, if any.

Syntax	Description
string toText( const string &fmt, unsigned int fsprec, const string &nlsParam = "") const;	Returns a `string` representation for the timestamp in the format specified.
UString toText( const UString &fmt, unsigned int fsprec, const UString &nlsParam) const;	Returns a `UString` representation for the timestamp in the format specified; globalization enabled.

Parameter	Description
fmt	The format string.
fsprec	The precision for the fractional second component of `Timestamp`.
nlsParam	The `NLS` parameters string. If `nlsParam` is specified, this determines the NLS parameters to be used for the conversion. If `nlsParam` is not specified, the `NLS` parameters are picked up from `envp`.