Informix JDBC Driver Programmer's Guide Manipulating Informix Data Types

The Informix INTERVAL data type stores a value that represents a span of time. INTERVAL data types are divided into two types: year-month intervals and day-time intervals. A year-month interval can represent a span of years and months, and a day-time interval can represent a span of days, hours, minutes, seconds, and fractions of a second. For more information about the INTERVAL data type and definitions of qualifier, precision, and fraction, refer to the following manuals:

• Informix Guide to SQL: Tutorial
• Informix Guide to SQL: Reference
• Informix Guide to SQL: Syntax

The com.informix.lang.Interval class is an Informix-specific extension to the JDBC 2.0 specification from Sun Microsystems. Interval is the base class for the INTERVAL data type. Interval has two subclasses: IntervalYM (for year-month qualifiers) and IntervalDF (for day-time qualifiers). You use these subclasses to actually create and manipulate INTERVAL data types.

You can use string qualifiers to manipulate INTERVAL data types, but using binary qualifiers results in faster performance. The following variables are defined in the Interval base class and represent the time unit (start and end code) of a field in the binary qualifier.

The IntervalYM and IntervalDF classes inherit these variables from the Interval base class.

You can use the following methods to extract information about binary qualifiers. Here are the signatures and descriptions of each method:

public static byte getEndCode(short qualifier)

This method extracts the ending field code (one of the TU_XXX variables) from a qualifier.

public static java.lang.String getFieldName(byte code)

This method takes the TU_XXX value of part of an interval and returns the string value. For example, getFieldName(TU_YEAR) returns the string YEAR.

public static java.lang.String getIfxTypeName(int type, short qual)

This method takes a qualifier and returns the entire name of the interval in string form.

public static byte getLength(short qualifier)

This method extracts the length of a qualifier.

public static short getQualifier(byte length, byte startCode, byte endCode) throws

java.sql.SQLException

This method creates a binary qualifier from a length, start code (TU_XXX), and end code (TU_XXX). For example, getQualifier(4, TU_YEAR, TU_MONTH) creates a binary representation of the YEAR TO MONTH qualifier.

public static byte getScale(short qualifier)

This method returns the number of digits in the FRACTION part of a day-time qualifier.

public static byte getStartCode(short qualifier)

This method extracts the starting field code (one of the TU_XXX variables) from a qualifier.

The IntervalYM and IntervalDF classes inherit these methods from Interval.

The com.informix.lang.IntervalYM class allows you to manipulate year-month intervals.

The following constructors allow you to create year-month intervals. Here are the signatures and descriptions of each constructor:

public IntervalYM() throws java.sql.SQLException

This is the default constructor.

public IntervalYM(java.sql.Timestamp t1, java.sql.Timestamp t2) throws

java.sql.SQLException

This constructor creates an interval from two timestamps.

public IntervalYM(int years, int months) throws java.sql.SQLException

This constructor creates a year-month interval from year and month values. Large month values are converted to years.

public IntervalYM(java.sql.String string) throws java.sql.SQLException

This constructor creates a year-month interval from a string. For information about string INTERVAL formats, refer to the Informix Guide to SQL: Syntax.

public IntervalYM(java.sql.String string, int length, byte startCode, byte

endCode) throws java.sql.SQLException

This constructor creates a year-month interval from a string and qualifier information. For information about string INTERVAL formats, refer to the Informix Guide to SQL: Syntax.

The following methods allow you to manipulate year-month intervals. Here are the signatures and descriptions of each method:

boolean equals(java.lang.Object other)

This method compares two intervals for equality.

void fromString(java.lang.String other)

This method sets the values for the interval from a string.

long getMonths()

This method returns the number of months in the interval.

boolean greaterThan(IntervalYM other)

This method compares the first interval to the second to see if the first is longer.

boolean lessThan(IntervalYM other)

This method compares the first interval to the second to see if the second is longer.

void set(int years, int months)

This method sets the values for the interval from year and month values. Large month values are converted to years.

void set(java.lang.String string)

This method sets the values for the interval from a string.

void set(java.sql.Timestamp t1, java.sql.Timestamp t2)

This method sets the values for the interval from two timestamps.

void setQualifier(int length, byte startCode, byte endCode)

This method sets the qualifier from the length, start code, and end code.

void setQualifier(short qualifier)

This method sets the qualifier using an existing qualifier.

java.lang.String toString()

This method creates a string representation of the interval in the format yyyy-mm. The fields present depend on the qualifier. Blanks replace leading zeros.

The com.informix.lang.IntervalDF class allows you to manipulate day-time intervals.

The following constructors allow you to create day-time intervals. Here are the signatures and descriptions of each constructor:

public IntervalDF() throws java.sql.SQLException

This is the default constructor.

public IntervalDF(java.sql.Timestamp t1, java.sql.Timestamp t2) throws

java.sql.SQLException

This constructor creates an interval from two timestamps.

public IntervalDF(long seconds, long nanos) throws java.sql.SQLException

This constructor creates a day-time interval from second and nanosecond values. Large second values are converted to minutes, hours, or days.

public IntervalDF(java.sql.String string) throws java.sql.SQLException

This constructor creates a day-time interval from a string. For information about string INTERVAL formats, refer to the Informix Guide to SQL: Syntax.

public IntervalDF(java.sql.String string, int length, byte startCode, byte

endCode) throws java.sql.SQLException

This constructor creates a day-time interval from a string and qualifier information. For information about string INTERVAL formats, refer to the Informix Guide to SQL: Syntax.

The following methods allow you to manipulate day-time intervals. Here are the signatures and descriptions of each method:

boolean equals(java.lang.Object other)

This method compares two intervals for equality.

void fromString(java.lang.String other)

This method sets the values for the interval from a string.

long getNanoSeconds()

This method returns the number of nanoseconds in the interval.

long getSeconds()

This method returns the number of seconds in the interval.

boolean greaterThan(IntervalDF other)

This method compares the first interval to the second to see if the first is longer.

boolean lessThan(IntervalDF other)

This method compares the first interval to the second to see if the second is longer.

void set(long seconds, long nanos)

This method sets the values for the interval from second and nanosecond values. Large second values are converted to minutes, hours, or days.

void set(java.lang.String string)

This method sets the values for the interval from a string.

void set(java.sql.Timestamp t1, java.sql.Timestamp t2)

This method sets the values for the interval from two timestamps.

void setQualifier(int length, byte startCode, byte endCode)

This method sets the qualifier from the length, start code, and end code.

java.lang.String toString()

This method creates a string representation of the interval in the format ddddd hh:mm:ss.nano. The fields present depend on the qualifier. Blanks replace leading zeros.

The Intervaldemo.java program, which is included in Informix JDBC Driver, shows how to insert into and select from the two types of INTERVAL data types.