(ODBC SQL types affected: BINARY, VARBINARY, LONGVARBINARY)
ODBC_BINMODE_PASSTHRU: Passthru BINARY data
ODBC_BINMODE_RETURN: Return as is
ODBC_BINMODE_CONVERT: Convert to char and return
When binary SQL data is converted to character C data, each byte (8 bits) of source data is represented as two ASCII characters. These characters are the ASCII character representation of the number in its hexadecimal form. For example, a binary 00000001 is converted to "01" and a binary 11111111 is converted to "FF".
表格 1. LONGVARBINARY handling
| binmode | longreadlen | result |
|---|---|---|
| ODBC_BINMODE_PASSTHRU | 0 | passthru |
| ODBC_BINMODE_RETURN | 0 | passthru |
| ODBC_BINMODE_CONVERT | 0 | passthru |
| ODBC_BINMODE_PASSTHRU | 0 | passthru |
| ODBC_BINMODE_PASSTHRU | >0 | passthru |
| ODBC_BINMODE_RETURN | >0 | return as is |
| ODBC_BINMODE_CONVERT | >0 | return as char |
If odbc_fetch_into() is used, passthru means that an empty string is returned for these columns.
If result_id is 0, the settings apply as default for new results.
注: Default for longreadlen is 4096 and binmode defaults to ODBC_BINMODE_RETURN. Handling of binary long columns is also affected by odbc_longreadlen()