数据类型的处理(提取自FMDB)

if ((!obj) || ((NSNull *)obj == [NSNull null])) {

sqlite3_bind_null(pStmt, idx);

}

// FIXME - someday check the return codes on these binds.

else if ([obj isKindOfClass:[NSData class]]) {

const void *bytes = [obj bytes];

if (!bytes) {

// it's an empty NSData object, aka [NSData data].

// Don't pass a NULL pointer, or sqlite will bind a SQL null instead of a blob.

bytes = "";

}

sqlite3_bind_blob(pStmt, idx, bytes, (int)[obj length], SQLITE_STATIC);

}

else if ([obj isKindOfClass:[NSDate class]]) {

if (self.hasDateFormatter)

sqlite3_bind_text(pStmt, idx, [[self stringFromDate:obj] UTF8String], -1, SQLITE_STATIC);

else

sqlite3_bind_double(pStmt, idx, [obj timeIntervalSince1970]);

}

else if ([obj isKindOfClass:[NSNumber class]]) {

if (strcmp([obj objCType], @encode(BOOL)) == 0) {

sqlite3_bind_int(pStmt, idx, ([obj boolValue] ? 1 : 0));

}

else if (strcmp([obj objCType], @encode(int)) == 0) {

sqlite3_bind_int64(pStmt, idx, [obj longValue]);

}

else if (strcmp([obj objCType], @encode(long)) == 0) {

sqlite3_bind_int64(pStmt, idx, [obj longValue]);

}

else if (strcmp([obj objCType], @encode(long long)) == 0) {

sqlite3_bind_int64(pStmt, idx, [obj longLongValue]);

}

else if (strcmp([obj objCType], @encode(unsigned long long)) == 0) {

sqlite3_bind_int64(pStmt, idx, (longlong)[obj unsignedLongLongValue]);

}

else if (strcmp([obj objCType], @encode(float)) == 0) {

sqlite3_bind_double(pStmt, idx, [obj floatValue]);

}

else if (strcmp([obj objCType], @encode(double)) == 0) {

sqlite3_bind_double(pStmt, idx, [obj doubleValue]);

}

else {

sqlite3_bind_text(pStmt, idx, [[obj description] UTF8String], -1, SQLITE_STATIC);

}

}

else {

sqlite3_bind_text(pStmt, idx, [[obj description] UTF8String], -1, SQLITE_STATIC);

}