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authorunknown <sergefp@mysql.com>2006-06-14 21:06:02 +0400
committerunknown <sergefp@mysql.com>2006-06-14 21:06:02 +0400
commit1a9fae81cb5018f8706d49f1032053355ce701c4 (patch)
tree4c138ddae81554696f5cc83ae8a2fe38c39b3112 /sql/structs.h
parent6297d1ab38d1b2eb56c965c3cb682ac20b97296b (diff)
downloadmariadb-git-1a9fae81cb5018f8706d49f1032053355ce701c4.tar.gz
Better comments in KEY_PART_INFO struct
Diffstat (limited to 'sql/structs.h')
-rw-r--r--sql/structs.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/sql/structs.h b/sql/structs.h
index 081ada88bf7..2037496635a 100644
--- a/sql/structs.h
+++ b/sql/structs.h
@@ -70,7 +70,13 @@ typedef struct st_key_part_info { /* Info about a key part */
Field *field;
uint offset; /* offset in record (from 0) */
uint null_offset; /* Offset to null_bit in record */
- uint16 length; /* Length of key_part */
+ uint16 length; /* Length of keypart value in bytes */
+ /*
+ Number of bytes required to store the keypart value. This may be
+ different from the "length" field as it also counts
+ - possible NULL-flag byte (see HA_KEY_NULL_LENGTH)
+ - possible HA_KEY_BLOB_LENGTH bytes needed to store actual value length.
+ */
uint16 store_length;
uint16 key_type;
uint16 fieldnr; /* Fieldnum in UNIREG */