mirror of
https://github.com/MariaDB/server.git
synced 2025-01-31 11:01:52 +01:00
67ce247965
Renamed HA_VAR_LENGTH to HA_VAR_LENGTH_PART Renamed in all files FIELD_TYPE_STRING and FIELD_TYPE_VAR_STRING to MYSQL_TYPE_STRING and MYSQL_TYPE_VAR_STRING to make it easy to catch all possible errors Added support for VARCHAR KEYS to heap Removed support for ISAM Now only long VARCHAR columns are changed to TEXT on demand (not CHAR) Internal temporary files can now use fixed length tables if the used VARCHAR columns are short
403 lines
11 KiB
C++
403 lines
11 KiB
C++
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Functions to handle keys and fields in forms */
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#include "mysql_priv.h"
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/*
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** Search after with key field is. If no key starts with field test
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** if field is part of some key.
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**
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** returns number of key. keylength is set to length of key before
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** (not including) field
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** Used when calculating key for NEXT_NUMBER
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*/
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int find_ref_key(TABLE *table,Field *field, uint *key_length)
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{
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reg2 int i;
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reg3 KEY *key_info;
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uint fieldpos;
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fieldpos= field->offset();
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/* Test if some key starts as fieldpos */
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for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++)
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{
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if (key_info->key_part[0].offset == fieldpos)
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{ /* Found key. Calc keylength */
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*key_length=0;
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return(i); /* Use this key */
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}
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}
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/* Test if some key contains fieldpos */
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for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++)
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{
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uint j;
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KEY_PART_INFO *key_part;
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*key_length=0;
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for (j=0, key_part=key_info->key_part ;
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j < key_info->key_parts ;
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j++, key_part++)
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{
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if (key_part->offset == fieldpos)
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return(i); /* Use this key */
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*key_length+=key_part->store_length;
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}
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}
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return(-1); /* No key is ok */
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}
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/*
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Copy part of a record that forms a key or key prefix to a buffer.
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SYNOPSIS
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key_copy()
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to_key buffer that will be used as a key
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from_record full record to be copied from
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key_info descriptor of the index
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key_length specifies length of all keyparts that will be copied
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DESCRIPTION
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The function takes a complete table record (as e.g. retrieved by
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handler::index_read()), and a description of an index on the same table,
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and extracts the first key_length bytes of the record which are part of a
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key into to_key. If length == 0 then copy all bytes from the record that
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form a key.
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RETURN
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None
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*/
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void key_copy(byte *to_key, byte *from_record, KEY *key_info, uint key_length)
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{
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uint length;
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KEY_PART_INFO *key_part;
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if (key_length == 0)
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key_length= key_info->key_length;
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for (key_part= key_info->key_part; (int) key_length > 0; key_part++)
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{
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if (key_part->null_bit)
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{
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*to_key++= test(from_record[key_part->null_offset] &
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key_part->null_bit);
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key_length--;
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}
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if (key_part->key_part_flag & HA_BLOB_PART)
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{
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char *pos;
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ulong blob_length= ((Field_blob*) key_part->field)->get_length();
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key_length-= HA_KEY_BLOB_LENGTH;
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((Field_blob*) key_part->field)->get_ptr(&pos);
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length=min(key_length, key_part->length);
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set_if_smaller(blob_length, length);
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int2store(to_key, (uint) blob_length);
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to_key+= HA_KEY_BLOB_LENGTH; // Skip length info
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memcpy(to_key, pos, blob_length);
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}
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else if (key_part->key_part_flag & HA_VAR_LENGTH_PART)
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{
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key_length-= HA_KEY_BLOB_LENGTH;
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length= min(key_length, key_part->length);
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key_part->field->get_key_image(to_key, length, Field::itRAW);
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to_key+= HA_KEY_BLOB_LENGTH;
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}
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else
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{
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length= min(key_length, key_part->length);
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memcpy(to_key, from_record + key_part->offset, (size_t) length);
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}
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to_key+= length;
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key_length-= length;
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}
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}
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/*
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Restore a key from some buffer to record.
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SYNOPSIS
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key_restore()
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to_record record buffer where the key will be restored to
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from_key buffer that contains a key
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key_info descriptor of the index
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key_length specifies length of all keyparts that will be restored
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DESCRIPTION
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This function converts a key into record format. It can be used in cases
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when we want to return a key as a result row.
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RETURN
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None
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*/
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void key_restore(byte *to_record, byte *from_key, KEY *key_info,
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uint key_length)
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{
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uint length;
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KEY_PART_INFO *key_part;
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if (key_length == 0)
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{
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key_length= key_info->key_length;
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}
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for (key_part= key_info->key_part ; (int) key_length > 0 ; key_part++)
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{
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if (key_part->null_bit)
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{
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if (*from_key++)
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to_record[key_part->null_offset]|= key_part->null_bit;
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else
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to_record[key_part->null_offset]&= ~key_part->null_bit;
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key_length--;
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}
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if (key_part->key_part_flag & HA_BLOB_PART)
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{
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uint blob_length= uint2korr(from_key);
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from_key+= HA_KEY_BLOB_LENGTH;
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key_length-= HA_KEY_BLOB_LENGTH;
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((Field_blob*) key_part->field)->set_ptr((ulong) blob_length,
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(char*) from_key);
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length= key_part->length;
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}
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else if (key_part->key_part_flag & HA_VAR_LENGTH_PART)
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{
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key_length-= HA_KEY_BLOB_LENGTH;
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length= min(key_length, key_part->length);
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key_part->field->set_key_image(from_key, length);
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from_key+= HA_KEY_BLOB_LENGTH;
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}
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else
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{
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length= min(key_length, key_part->length);
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memcpy(to_record + key_part->offset, from_key, (size_t) length);
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}
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from_key+= length;
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key_length-= length;
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}
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}
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/*
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Compare if a key has changed
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SYNOPSIS
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key_cmp_if_same()
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table TABLE
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key key to compare to row
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idx Index used
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key_length Length of key
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NOTES
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In theory we could just call field->cmp() for all field types,
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but as we are only interested if a key has changed (not if the key is
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larger or smaller than the previous value) we can do things a bit
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faster by using memcmp() instead.
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RETURN
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0 If key is equal
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1 Key has changed
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*/
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bool key_cmp_if_same(TABLE *table,const byte *key,uint idx,uint key_length)
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{
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uint length;
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KEY_PART_INFO *key_part;
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for (key_part=table->key_info[idx].key_part;
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(int) key_length > 0;
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key_part++, key+=length, key_length-=length)
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{
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if (key_part->null_bit)
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{
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key_length--;
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if (*key != test(table->record[0][key_part->null_offset] &
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key_part->null_bit))
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return 1;
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if (*key)
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{
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length=key_part->store_length;
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continue;
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}
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key++;
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}
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if (key_part->key_part_flag & (HA_BLOB_PART | HA_VAR_LENGTH_PART))
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{
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if (key_part->field->key_cmp(key, key_part->length))
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return 1;
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length=key_part->length+HA_KEY_BLOB_LENGTH;
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}
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else
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{
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length=min(key_length,key_part->length);
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if (!(key_part->key_type & (FIELDFLAG_NUMBER+FIELDFLAG_BINARY+
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FIELDFLAG_PACK)))
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{
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CHARSET_INFO *cs= key_part->field->charset();
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uint char_length= key_part->length / cs->mbmaxlen;
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const byte *pos= table->record[0] + key_part->offset;
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if (length > char_length)
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{
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char_length= my_charpos(cs, pos, pos + length, char_length);
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set_if_smaller(char_length, length);
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}
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if (cs->coll->strnncollsp(cs,
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(const uchar*) key, length,
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(const uchar*) pos, char_length, 0))
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return 1;
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}
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else if (memcmp(key,table->record[0]+key_part->offset,length))
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return 1;
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}
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}
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return 0;
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}
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/* unpack key-fields from record to some buffer */
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/* This is used to get a good error message */
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void key_unpack(String *to,TABLE *table,uint idx)
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{
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KEY_PART_INFO *key_part,*key_part_end;
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Field *field;
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String tmp;
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DBUG_ENTER("key_unpack");
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to->length(0);
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for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
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table->key_info[idx].key_parts ;
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key_part < key_part_end;
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key_part++)
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{
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if (to->length())
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to->append('-');
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if (key_part->null_bit)
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{
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if (table->record[0][key_part->null_offset] & key_part->null_bit)
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{
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to->append("NULL", 4);
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continue;
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}
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}
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if ((field=key_part->field))
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{
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field->val_str(&tmp);
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if (key_part->length < field->pack_length())
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tmp.length(min(tmp.length(),key_part->length));
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to->append(tmp);
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}
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else
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to->append("???", 3);
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}
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DBUG_VOID_RETURN;
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}
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/*
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Return 1 if any field in a list is part of key or the key uses a field
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that is automaticly updated (like a timestamp)
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*/
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bool check_if_key_used(TABLE *table, uint idx, List<Item> &fields)
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{
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List_iterator_fast<Item> f(fields);
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KEY_PART_INFO *key_part,*key_part_end;
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for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
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table->key_info[idx].key_parts ;
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key_part < key_part_end;
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key_part++)
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{
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Item_field *field;
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if (key_part->field == table->timestamp_field)
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return 1; // Can't be used for update
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f.rewind();
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while ((field=(Item_field*) f++))
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{
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if (key_part->field == field->field)
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return 1;
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}
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}
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/*
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If table handler has primary key as part of the index, check that primary
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key is not updated
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*/
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if (idx != table->primary_key && table->primary_key < MAX_KEY &&
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(table->file->table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX))
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return check_if_key_used(table, table->primary_key, fields);
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return 0;
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}
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/*
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Compare key in row to a given key
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SYNOPSIS
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key_cmp()
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key_part Key part handler
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key Key to compare to value in table->record[0]
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key_length length of 'key'
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RETURN
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The return value is SIGN(key_in_row - range_key):
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0 Key is equal to range or 'range' == 0 (no range)
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-1 Key is less than range
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1 Key is larger than range
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*/
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int key_cmp(KEY_PART_INFO *key_part, const byte *key, uint key_length)
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{
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uint store_length;
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for (const byte *end=key + key_length;
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key < end;
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key+= store_length, key_part++)
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{
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int cmp;
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store_length= key_part->store_length;
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if (key_part->null_bit)
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{
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/* This key part allows null values; NULL is lower than everything */
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register bool field_is_null= key_part->field->is_null();
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if (*key) // If range key is null
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{
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/* the range is expecting a null value */
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if (!field_is_null)
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return 1; // Found key is > range
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/* null -- exact match, go to next key part */
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continue;
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}
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else if (field_is_null)
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return -1; // NULL is less than any value
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key++; // Skip null byte
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store_length--;
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}
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if ((cmp=key_part->field->key_cmp((byte*) key, key_part->length)) < 0)
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return -1;
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if (cmp > 0)
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return 1;
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}
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return 0; // Keys are equal
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}
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