SQL to C: Day-Time Intervals
The identifiers for the day-time interval ODBC SQL data types are the following:
- 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;
Phản hồi
https://aka.ms/ContentUserFeedback.
Sắp ra mắt: Trong năm 2024, chúng tôi sẽ dần gỡ bỏ Sự cố với GitHub dưới dạng cơ chế phản hồi cho nội dung và thay thế bằng hệ thống phản hồi mới. Để biết thêm thông tin, hãy xem:Gửi và xem ý kiến phản hồi dành cho