OCCI Classes and Methods, 8 of 22

Date Class

The Date class specifies the abstraction for a SQL DATE data item. The Date class also adds formatting and parsing operations to support the OCCI escape syntax for date values.

Since SQL92 DATE is a subset of Oracle Date, this class can be used to support both.

To create a null Date object, use the syntax:

Date();

To create a copy of a Date object, use the syntax:

Date(const Date &a);

To create a Date object using integer parameters, where:

Variable	Value
year	-4712 to 9999, except 0
month	1 to 12
day	1 to 31
minutes	0 to 59
seconds	0 to 59

use the syntax:

Date(const Environment *envp,
   int year = 1,
   unsigned int month = 1,
   unsigned int day = 1,
   unsigned int hour = 0,
   unsigned int minute = 0,
   unsigned int seconds = 0);

Objects from the Date class can be used as standalone class objects in client side numerical computations and also used to fetch from and set to the database.

The following code example demonstrates a Date column value being retrieved from the database, a bind using a Date object, and a computation using a standalone Date object:

/* Create a connection */
Environment *env = Environment::createEnvironment(Environment::DEFAULT);
Connection *conn = env->createConnection(user, passwd, db);

/* Create a statement and associate a DML statement to it */
string sqlStmt = "SELECT job-id, start_date from JOB_HISTORY
                            where end_date = :x";
Statement *stmt = conn->createStatement(sqlStmt);

/* Create a Date object and bind it to the statement */
Date edate(env, 2000, 9, 3, 23, 30, 30);
stmt->setDate(1, edate);
ResultSet *rset = stmt->executeQuery();

/* Fetch a date from the database */
while(rset->next())
{
   Date sd = rset->getDate(2);
   Date temp = sd;    /*assignment operator */
   /* Methods on Date */
   temp.getDate(year, month, day, hour, minute, second);
   temp.setMonths(2);
   IntervalDS inter = temp.daysBetween(sd);
   .
   .
   .
}

Summary of Date Methods

Table 8-8 Date Methods

Method	Summary
addDays()	Return a `Date` object with n days added.
addMonths()	Return a `Date` object with n months added.
daysBetween()	Return the number of days between the current `Date` object and the date specified.
fromBytes()	Convert an external `Bytes` representation of a `Date` object to a `Date` object.
fromText()	Convert the date from a given input string with format and nls parameters specified.
getDate()()	Return the date and time components of the `Date` object.
getSystemDate()	Return a `Date` object containing the system date.
isNull()	Returns `true` if `Date` is null`; otherwise returns` `false`.
lastDay()	Returns a `Date` that is the last day of the month.
nextDay()	Returns a `Date` that is the date of the next day of the week.
operator=()	Assign the values of a date to another.
operator==()	Returns `true` if `a` and `b` are the same, `false` otherwise.
operator!=()	Returns `true` if `a` and `b` are unequal, `false` otherwise.
operator>()	Returns `true` if `a` is past `b`, `false` otherwise.
operator>=()	Returns `true` if `a` is past `b or equal to b`, `false` otherwise.
operator<()	Returns `true` if `a` is before `b`, `false` otherwise.
operator<=()	Returns `true` if `a` is before `b`, or equal to b, `false` otherwise.
setDate()	Set the date from the date components input.
setNull()	Sets the object state to null.
toBytes()	Converts the `Date` object into an external `Bytes` representation.
toText()	Get the `Date` object as a string.
toZone()	Return a `Date` object converted from one time zone to another.

addDays()

This method adds a specified number of days to the Date object and returns the new date.

Syntax

Date addDays(int i) const;

Parameters

i

The number of days to be added to the current Date object.

addMonths()

This method adds a specified number of months to the Date object and returns the new date.

Syntax

Date addMonths(int i) const;

Parameters

i

The number of months to be added to the current Date object.

daysBetween()

This method returns the number of days between the current Date object and the date specified.

Syntax

IntervalDS daysBetween(const Date &d) const;

Parameters

d

The date to be used to compute the days between.

fromBytes()

This method converts a Bytes object to a Date object.

Syntax

void fromBytes(const Bytes &byteStream,
const Environment *envp = NULL);

Parameters

byteStream

Date in external format in the form of Bytes.

envp

The OCCI environment.

fromText()

This method converts a string object to a Date object.

Syntax

void fromText(const string &datestr,
   const string &fmt = "",
   const string &nlsParam = "",
   const Environment *envp = NULL);

Parameters

datestr

The date string to be converted.

fmt

The format string.

nlsParam

A string specifying the nls parameters to be used.

envp

The environment from which the nls parameters are to be obtained.

getDate()

This method returns the date in the form of the date components year, month, day, hour, minute, seconds.

Syntax

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

Parameters

year

The year component of the date.

month

The month component of the date.

day

The day component of the date.

hour

The hour component of the date.

min

The minutes component of the date.

seconds

The seconds component of the date.

getSystemDate()

This method returns the system date.

Syntax

static Date getSystemDate(const Environment *envp);

Parameters

envp

The environment in which the system date is returned.

isNull()

This method tests whether the Date is null. If the Date is null, true is returned; otherwise, false is returned.

Syntax

bool isNull() const;

lastDay()

This method returns a date representing the last day of the current month.

Syntax

Date lastDay() const;

nextDay()

This method returns a date representing the day after the day of the week specified.

Syntax

Date nextDay(const string &dow) const;

Parameters

dow

A string representing the day of the week.

operator=()

This method assigns the date object on the right side of the equal (=) sign to the date object on the left side of the equal (=) sign.

Syntax

Date& operator=(const Date &d);

Parameters

d

The date object that is assigned.

operator==()

This method compares the dates specified. If the dates are equal, true is returned; otherwise, false is returned.

Syntax

bool operator==(const Date &a,
   const Date &b);

Parameters

a, b

The dates that are compared for equality.

operator!=()

This method compares the dates specified. If the dates are not equal then true is returned; otherwise, false is returned.

Syntax

bool operator!=(const Date &a,
   const Date &b);

Parameters

a, b

The dates that are compared for inequality.

operator>()

This method compares the dates specified. If the first date is in the future relative to the second date then true is returned; otherwise, false is returned. If either date is null then false is returned. If the dates are not the same type then false is returned.

Syntax

bool operator>(const Date &a,
   const Date &b);

Parameters

a, b

The dates that are compared.

operator>=()

This method compares the dates specified. If the first date is in the future relative to the second date or the dates are equal then true is returned; otherwise, false is returned. If either date is null then false is returned. If the dates are not the same type then false is returned.

Syntax

bool operator>=(const Date &a,
   const Date &b);

Parameters

a, b

The dates that are compared.

operator<()

This method compares the dates specified. If the first date is in the past relative to the second date then true is returned; otherwise, false is returned. If either date is null then false is returned. If the dates are not the same type then false is returned.

Syntax

bool operator<(const Date &a,
   const Date &b);

Parameters

a, b

The dates that are compared.

operator<=()

This method compares the dates specified. If the first date is in the past relative to the second date or the dates are equal then true is returned; otherwise, false is returned. If either date is null then false is returned. If the dates are not the same type then false is returned.

Syntax

bool operator<=(const Date &a,
   const Date &b);

Parameters

a, b

The dates that are compared.

setDate()

This method sets the date to the values specified.

Syntax

void setDate(int year = 1,
   unsigned int month = 1,
   unsigned int day = 1,
   unsigned int hour = 0,
   unsigned int minute = 0,
   unsigned int seconds = 0);

Parameters

year

The argument specifying the year value.

Valid values are -4713 through 9999.

month

The argument specifying the month value.

Valid values are 1 through 12.

day

The argument specifying the day value.

Valid values are 1 through 31.

hour

The argument specifying the hour value.

Valid values are 0 through 23.

minute

The argument specifying the minutes value.

Valid values are 0 through 59 .

seconds

The argument specifying the seconds value.

Valid values are 0 through 59.

setNull()

This method set the date to atomically null.

Syntax

void setNull();

toBytes()

This method returns the date in Bytes representation.

Syntax

Bytes toBytes() const;

toText()

This method returns a string with the value of this date formatted using fmt and nlsParam.

Syntax

string toText(const string &fmt = "",
   const string &nlsParam = "") const;

Parameters

fmt

The format string.

nlsParam

A string specifying the nls parameters to be used.

toZone()

This method returns Date value converted from one time zone to another.

Valid values are:

Zone code	Value
`AST, ADT`	Atlantic Standard or Daylight Time
`BST, BDT`	Bering Standard or Daylight Time
`CST, CDT`	Central Standard or Daylight Time
`EST, EDT`	Eastern Standard or Daylight Time
`GMT`	Greenwich Mean Time
`HST, HDT`	Alaska-Hawaii Standard Time or Daylight Time
`MST, MDT`	Mountain Standard or Daylight Time
`NST`	Newfoundland Standard Time
`PST, PDT`	Pacific Standard or Daylight Time
`YST, YDT`	Yukon Standard or Daylight Time

Syntax

Date toZone(const string &zone1,
   const string &zone2) const;