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SQL to C: Day-Time Intervals

The identifiers for the day-time interval ODBC SQL data types are:

SQL_INTERVAL_DAY

SQL_INTERVAL_DAY_TO_MINUTE

SQL_INTERVAL_HOUR

SQL_INTERVAL_DAY_TO_SECOND

SQL_INTERVAL_MINUTE

SQL_INTERVAL_HOUR_TO_MINUTE

SQL_INTERVAL_SECOND

SQL_INTERVAL_HOUR_TO_SECOND

SQL_INTERVAL_DAY_TO_HOUR

SQL_INTERVAL_MINUTE_TO_SECOND

The following table shows the ODBC C data types to which day-time interval SQL data may be converted. For an explanation of the columns and terms in the table, see Converting Data from SQL to C Data Types.

C type identifier

Test

*TargetValuePtr

*StrLen_or_IndPtr

SQLSTATE

All day-time C interval types

Trailing fields portion not truncated

Trailing fields portion truncated

Leading precision of target is not big enough to hold data from source

Data

Truncated data

Undefined

Length of data

Length of data

Undefined

n/a

01S07

22015

SQL_C_STINYINT[b] SQL_C_UTINYINT[b] SQL_C_USHORT[b] SQL_C_SHORT[b] SQL_C_SLONG[b] SQL_C_ULONG[b] SQL_C_NUMERIC[b] SQL_C_BIGINT[b]

Interval precision was a single field and the data was converted without truncation

Interval precision was a single field and truncated fractional

Interval precision was a single field and truncated whole

Interval precision was not a single field

Data

Truncated data

Truncated data

Undefined

Size of the C data type

Length of data

Length of data

Size of the C data type

n/a

01S07

22003

07006

SQL_C_BINARY

Byte length of data <= BufferLength

Byte length of data > BufferLength

Data

Undefined

Length of data

Undefined

n/a

22003

SQL_C_CHAR

Character byte length < BufferLength

Number of whole (as opposed to fractional) digits < BufferLength

Number of whole (as opposed to fractional) digits >= BufferLength

Data

Truncated data

Undefined

Size of the C data type

Size of the C data type

Undefined

n/a

01004

22003

SQL_C_WCHAR

Character length < BufferLength

Number of whole (as opposed to fractional) digits < BufferLength

Number of whole (as opposed to fractional) digits >= BufferLength

Data

Truncated data

Undefined

Size of the C data type

Size of the C data type

Undefined

n/a

01004

22003

[a]   A day-time interval SQL type can be converted to any day-time interval C type.

[b]   If the interval precision is a single field (one of DAY, HOUR, MINUTE, or SECOND), the interval SQL type can be converted to any exact numeric (SQL_C_STINYINT, SQL_C_UTINYINT, SQL_C_USHORT, SQL_C_SHORT, SQL_C_SLONG, SQL_C_ULONG, or SQL_C_NUMERIC).

The default conversion of an interval SQL type is to the corresponding C interval data type. The application then binds the column or parameter (or sets the SQL_DESC_DATA_PTR field in the appropriate record of the ARD) to point to the initialized SQL_INTERVAL_STRUCT structure (or passes a pointer to the SQL_ INTERVAL_STRUCT structure as the TargetValuePtr argument in a call to SQLGetData).

The following example demonstrates how to transfer data from a column of type SQL_INTERVAL_DAY_TO_MINUTE into the SQL_INTERVAL_STRUCT structure such that it comes back as a DAY_TO_HOUR interval.

SQL_INTERVAL_STRUCT is;
SQLINTEGER    cbValue;
SQLUINTEGER   days, hours;

// Execute a select statement; "interval_column" is a column
// whose data type is SQL_INTERVAL_DAY_TO_MINUTE.
SQLExecDirect(hstmt, "SELECT interval_column FROM table", SQL_NTS);

// Bind
SQLBindCol(hstmt, 1, SQL_C_INTERVAL_DAY_TO_MINUTE, &is, sizeof(SQL_INTERVAL_STRUCT), &cbValue);

// Fetch
SQLFetch(hstmt);

// Process data
days = is.intval.day_second.day;
hours = is.intval.day_second.hour;
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