diff options
Diffstat (limited to 'sql/field.h')
| -rw-r--r-- | sql/field.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/sql/field.h b/sql/field.h index 7f17f8dad77..9db4f47a0f3 100644 --- a/sql/field.h +++ b/sql/field.h @@ -2129,6 +2129,23 @@ public: uchar *from_null_ptr,*to_null_ptr; my_bool *null_row; uint from_bit,to_bit; + /** + Number of bytes in the fields pointed to by 'from_ptr' and + 'to_ptr'. Usually this is the number of bytes that are copied from + 'from_ptr' to 'to_ptr'. + + For variable-length fields (VARCHAR), the first byte(s) describe + the actual length of the text. For VARCHARs with length + < 256 there is 1 length byte + >= 256 there is 2 length bytes + Thus, if from_field is VARCHAR(10), from_length (and in most cases + to_length) is 11. For VARCHAR(1024), the length is 1026. @see + Field_varstring::length_bytes + + Note that for VARCHARs, do_copy() will be do_varstring*() which + only copies the length-bytes (1 or 2) + the actual length of the + text instead of from/to_length bytes. @see get_copy_func() + */ uint from_length,to_length; Field *from_field,*to_field; String tmp; // For items |