byte*
trx_undo_rec_get_partial_row(
/*=========================*/
				/* out: pointer to remaining part of undo
				record */
	byte*		ptr,	/* in: remaining part in update undo log
				record of a suitable type, at the start of
				the stored index columns;
				NOTE that this copy of the undo log record must
				be preserved as long as the partial row is
				used, as we do NOT copy the data in the
				record! */
	dict_index_t*	index,	/* in: clustered index */
	dtuple_t**	row,	/* out, own: partial row */
	mem_heap_t*	heap)	/* in: memory heap from which the memory
				needed is allocated */
{
	dfield_t*	dfield;
	byte*		field;
	ulint		len;
	ulint		field_no;
	ulint		col_no;
	ulint		row_len;
	ulint		total_len;
	byte*		start_ptr;
	ulint		i;

	ut_ad(index && ptr && row && heap);

	row_len = dict_table_get_n_cols(index->table);

	*row = dtuple_create(heap, row_len);

	dict_table_copy_types(*row, index->table);

	start_ptr = ptr;

	total_len = mach_read_from_2(ptr);
	ptr += 2;

	for (i = 0;; i++) {

		if (ptr == start_ptr + total_len) {

			break;
		}

		ptr = trx_undo_update_rec_get_field_no(ptr, &field_no);

		col_no = dict_index_get_nth_col_no(index, field_no);

		ptr = trx_undo_rec_get_col_val(ptr, &field, &len);

		dfield = dtuple_get_nth_field(*row, col_no);

		dfield_set_data(dfield, field, len);
	}

	return(ptr);
}

void
row_upd_clust_index_replace_new_col_vals(
/*=====================================*/
	dtuple_t*	entry,	/* in/out: index entry where replaced */
	upd_t*		update)	/* in: update vector */
{
	upd_field_t*	upd_field;
	dfield_t*	dfield;
	dfield_t*	new_val;
	ulint		field_no;
	ulint		i;

	dtuple_set_info_bits(entry, update->info_bits);

	for (i = 0; i < upd_get_n_fields(update); i++) {

		upd_field = upd_get_nth_field(update, i);

		field_no = upd_field->field_no;

		dfield = dtuple_get_nth_field(entry, field_no);

		new_val = &(upd_field->new_val);

		dfield_set_data(dfield, new_val->data, new_val->len);
	}
}

dtuple_t*
row_rec_to_index_entry(
/*===================*/
				/* out, own: index entry built; see the
				NOTE below! */
	ulint		type,	/* in: ROW_COPY_DATA, or ROW_COPY_POINTERS:
				the former copies also the data fields to
				heap as the latter only places pointers to
				data fields on the index page */
	dict_index_t*	index,	/* in: index */
	rec_t*		rec,	/* in: record in the index;
				NOTE: in the case ROW_COPY_POINTERS
				the data fields in the row will point
				directly into this record, therefore,
				the buffer page of this record must be
				at least s-latched and the latch held
				as long as the dtuple is used! */
	mem_heap_t*	heap)	/* in: memory heap from which the memory
				needed is allocated */
{
	dtuple_t*	entry;
	dfield_t*	dfield;
	ulint		i;
	byte*		field;
	ulint		len;
	ulint		rec_len;
	byte*		buf;
	
	ut_ad(rec && heap && index);
	
	if (type == ROW_COPY_DATA) {
		/* Take a copy of rec to heap */
		buf = mem_heap_alloc(heap, rec_get_size(rec));
		rec = rec_copy(buf, rec);
	}

	rec_len = rec_get_n_fields(rec);
	
	entry = dtuple_create(heap, rec_len);

	dtuple_set_n_fields_cmp(entry,
				dict_index_get_n_unique_in_tree(index));
	ut_ad(rec_len == dict_index_get_n_fields(index));

	dict_index_copy_types(entry, index, rec_len);

	dtuple_set_info_bits(entry, rec_get_info_bits(rec));

	for (i = 0; i < rec_len; i++) {

		dfield = dtuple_get_nth_field(entry, i);
		field = rec_get_nth_field(rec, i, &len);

		dfield_set_data(dfield, field, len);
	}

	ut_ad(dtuple_check_typed(entry));

	return(entry);
}

void
rec_copy_prefix_to_dtuple(
/*======================*/
	dtuple_t*	tuple,		/* in: data tuple */
	rec_t*		rec,		/* in: physical record */
	ulint		n_fields,	/* in: number of fields to copy */
	mem_heap_t*	heap)		/* in: memory heap */
{
	dfield_t*	field;
	byte*		data;
	ulint		len;
	byte*		buf = NULL;
	ulint		i;
	
	ut_ad(rec_validate(rec));	
	ut_ad(dtuple_check_typed(tuple));

	dtuple_set_info_bits(tuple, rec_get_info_bits(rec));

	for (i = 0; i < n_fields; i++) {

		field = dtuple_get_nth_field(tuple, i);
		data = rec_get_nth_field(rec, i, &len);

		if (len != UNIV_SQL_NULL) {
			buf = mem_heap_alloc(heap, len);

			ut_memcpy(buf, data, len);
		}

		dfield_set_data(field, buf, len);
	}
}

/* Some non-inlined functions used in the MySQL interface: */
void 
dfield_set_data_noninline(
	dfield_t* 	field,	/* in: field */
	void*		data,	/* in: data */
	ulint		len)	/* in: length or UNIV_SQL_NULL */
{
	dfield_set_data(field, data, len);
}

/*******************************************************************//**
Converts an index record to a typed data tuple.
@return index entry built; does not set info_bits, and the data fields
in the entry will point directly to rec */
UNIV_INTERN
dtuple_t*
row_rec_to_index_entry_low(
/*=======================*/
	const rec_t*		rec,	/*!< in: record in the index */
	const dict_index_t*	index,	/*!< in: index */
	const ulint*		offsets,/*!< in: rec_get_offsets(rec, index) */
	ulint*			n_ext,	/*!< out: number of externally
					stored columns */
	mem_heap_t*		heap)	/*!< in: memory heap from which
					the memory needed is allocated */
{
	dtuple_t*	entry;
	dfield_t*	dfield;
	ulint		i;
	const byte*	field;
	ulint		len;
	ulint		rec_len;

	ut_ad(rec && heap && index);
	/* Because this function may be invoked by row0merge.c
	on a record whose header is in different format, the check
	rec_offs_validate(rec, index, offsets) must be avoided here. */
	ut_ad(n_ext);
	*n_ext = 0;

	rec_len = rec_offs_n_fields(offsets);

	entry = dtuple_create(heap, rec_len);

	dtuple_set_n_fields_cmp(entry,
				dict_index_get_n_unique_in_tree(index));
	ut_ad(rec_len == dict_index_get_n_fields(index));

	dict_index_copy_types(entry, index, rec_len);

	for (i = 0; i < rec_len; i++) {

		dfield = dtuple_get_nth_field(entry, i);
		field = rec_get_nth_field(rec, offsets, i, &len);

		dfield_set_data(dfield, field, len);

		if (rec_offs_nth_extern(offsets, i)) {
			dfield_set_ext(dfield);
			(*n_ext)++;
		}
	}

	ut_ad(dtuple_check_typed(entry));

	return(entry);
}

void
row_build_to_tuple(
/*===============*/
	dtuple_t*	row,	/* in/out: row built; see the NOTE below! */
	dict_index_t*	index,	/* in: clustered index */
	rec_t*		rec)	/* in: record in the clustered index;
				NOTE: the data fields in the row will point
				directly into this record, therefore,
				the buffer page of this record must be
				at least s-latched and the latch held
				as long as the row dtuple is used!
				NOTE 2: does not work with externally
				stored fields! */
{
	dict_table_t*	table;
	ulint		n_fields;
	ulint		i;
	dfield_t*	dfield;
	byte*		field;
	ulint		len;
	ulint		row_len;
	dict_col_t*	col;
	
	ut_ad(index && rec);
	ut_ad(index->type & DICT_CLUSTERED);

	table = index->table;
	row_len = dict_table_get_n_cols(table);

	dtuple_set_info_bits(row, rec_get_info_bits(rec));
	
	n_fields = dict_index_get_n_fields(index);

	ut_ad(n_fields == rec_get_n_fields(rec));

	dict_table_copy_types(row, table);

	for (i = 0; i < n_fields; i++) {

		col = dict_field_get_col(dict_index_get_nth_field(index, i));
		dfield = dtuple_get_nth_field(row, dict_col_get_no(col));
		field = rec_get_nth_field(rec, i, &len);

		dfield_set_data(dfield, field, len);
	}

	ut_ad(dtuple_check_typed(row));
}

/******************************************************************//**
Adds a string literal to a symbol table.
@return	symbol table node */
UNIV_INTERN
sym_node_t*
sym_tab_add_str_lit(
/*================*/
	sym_tab_t*	sym_tab,	/*!< in: symbol table */
	byte*		str,		/*!< in: string with no quotes around
					it */
	ulint		len)		/*!< in: string length */
{
	sym_node_t*	node;
	byte*		data;

	node = mem_heap_alloc(sym_tab->heap, sizeof(sym_node_t));

	node->common.type = QUE_NODE_SYMBOL;

	node->resolved = TRUE;
	node->token_type = SYM_LIT;

	node->indirection = NULL;

	dtype_set(dfield_get_type(&node->common.val),
		  DATA_VARCHAR, DATA_ENGLISH, 0);

	if (len) {
		data = mem_heap_alloc(sym_tab->heap, len);
		ut_memcpy(data, str, len);
	} else {
		data = NULL;
	}

	dfield_set_data(&(node->common.val), data, len);

	node->common.val_buf_size = 0;
	node->prefetch_buf = NULL;
	node->cursor_def = NULL;

	UT_LIST_ADD_LAST(sym_list, sym_tab->sym_list, node);

	node->sym_table = sym_tab;

	return(node);
}

void
row_upd_index_replace_new_col_vals(
/*===============================*/
	dtuple_t*	entry,	/* in/out: index entry where replaced */
	dict_index_t*	index,	/* in: index; NOTE that may also be a
				non-clustered index */
	upd_t*		update)	/* in: update vector */
{
	upd_field_t*	upd_field;
	dfield_t*	dfield;
	dfield_t*	new_val;
	ulint		field_no;
	dict_index_t*	clust_index;
	ulint		i;

	ut_ad(index);

	clust_index = dict_table_get_first_index(index->table);

	dtuple_set_info_bits(entry, update->info_bits);

	for (i = 0; i < upd_get_n_fields(update); i++) {

		upd_field = upd_get_nth_field(update, i);

		field_no = dict_index_get_nth_col_pos(index,
				dict_index_get_nth_col_no(clust_index,
							upd_field->field_no));
		if (field_no != ULINT_UNDEFINED) {
			dfield = dtuple_get_nth_field(entry, field_no);

			new_val = &(upd_field->new_val);

			dfield_set_data(dfield, new_val->data, new_val->len);
		}
	}
}

/******************************************************************//**
Adds an integer literal to a symbol table.
@return	symbol table node */
UNIV_INTERN
sym_node_t*
sym_tab_add_int_lit(
/*================*/
	sym_tab_t*	sym_tab,	/*!< in: symbol table */
	ulint		val)		/*!< in: integer value */
{
	sym_node_t*	node;
	byte*		data;

	node = mem_heap_alloc(sym_tab->heap, sizeof(sym_node_t));

	node->common.type = QUE_NODE_SYMBOL;

	node->resolved = TRUE;
	node->token_type = SYM_LIT;

	node->indirection = NULL;

	dtype_set(dfield_get_type(&node->common.val), DATA_INT, 0, 4);

	data = mem_heap_alloc(sym_tab->heap, 4);
	mach_write_to_4(data, val);

	dfield_set_data(&(node->common.val), data, 4);

	node->common.val_buf_size = 0;
	node->prefetch_buf = NULL;
	node->cursor_def = NULL;

	UT_LIST_ADD_LAST(sym_list, sym_tab->sym_list, node);

	node->sym_table = sym_tab;

	return(node);
}

/***************************************************************************
Loads a foreign key constraint to the dictionary cache. */
static
ulint
dict_load_foreign(
/*==============*/
			/* out: DB_SUCCESS or error code */
	char*	id)	/* in: foreign constraint id as a null-terminated
			string */
{	
	dict_foreign_t*	foreign;
	dict_table_t*	sys_foreign;
	btr_pcur_t	pcur;
	dict_index_t*	sys_index;
	dtuple_t*	tuple;
	mem_heap_t*	heap2;
	dfield_t*	dfield;
	rec_t*		rec;
	byte*		field;
	ulint		len;
	ulint		err;
	mtr_t		mtr;
	
	ut_ad(mutex_own(&(dict_sys->mutex)));

	heap2 = mem_heap_create(1000);
	
	mtr_start(&mtr);

	sys_foreign = dict_table_get_low("SYS_FOREIGN");
	sys_index = UT_LIST_GET_FIRST(sys_foreign->indexes);

	tuple = dtuple_create(heap2, 1);
	dfield = dtuple_get_nth_field(tuple, 0);

	dfield_set_data(dfield, id, ut_strlen(id));
	dict_index_copy_types(tuple, sys_index, 1);

	btr_pcur_open_on_user_rec(sys_index, tuple, PAGE_CUR_GE,
					BTR_SEARCH_LEAF, &pcur, &mtr);
	rec = btr_pcur_get_rec(&pcur);

	if (!btr_pcur_is_on_user_rec(&pcur, &mtr)
					|| rec_get_deleted_flag(rec)) {
		/* Not found */

		fprintf(stderr,
		"InnoDB: Error A: cannot load foreign constraint %s\n", id);

		btr_pcur_close(&pcur);
		mtr_commit(&mtr);
		mem_heap_free(heap2);
		
		return(DB_ERROR);
	}	

	field = rec_get_nth_field(rec, 0, &len);

	/* Check if the id in record is the searched one */
	if (len != ut_strlen(id) || ut_memcmp(id, field, len) != 0) {

		fprintf(stderr,
		"InnoDB: Error B: cannot load foreign constraint %s\n", id);

		btr_pcur_close(&pcur);
		mtr_commit(&mtr);
		mem_heap_free(heap2);
		
		return(DB_ERROR);
	}

	/* Read the table names and the number of columns associated
	with the constraint */

	mem_heap_free(heap2);
	
	foreign = dict_mem_foreign_create();

	foreign->n_fields = mach_read_from_4(rec_get_nth_field(rec, 5, &len));

	ut_a(len == 4);
	
	foreign->id = mem_heap_alloc(foreign->heap, ut_strlen(id) + 1);
				
	ut_memcpy(foreign->id, id, ut_strlen(id) + 1);

	field = rec_get_nth_field(rec, 3, &len);
							
	foreign->foreign_table_name = mem_heap_alloc(foreign->heap, 1 + len);
				
	ut_memcpy(foreign->foreign_table_name, field, len);
	foreign->foreign_table_name[len] = '\0';	
	
	field = rec_get_nth_field(rec, 4, &len);
							
	foreign->referenced_table_name = mem_heap_alloc(foreign->heap, 1 + len);
				
	ut_memcpy(foreign->referenced_table_name, field, len);
	foreign->referenced_table_name[len] = '\0';	

//.........这里部分代码省略.........

//.........这里部分代码省略.........
	/* Decide which fields to shorten: the algorithm is to look for
	a variable-length field that yields the biggest savings when
	stored externally */

	n_fields = 0;

	while (page_zip_rec_needs_ext(rec_get_converted_size(index, entry,
							     *n_ext),
				      dict_table_is_comp(index->table),
				      dict_index_get_n_fields(index),
				      dict_table_zip_size(index->table))) {
		ulint			i;
		ulint			longest		= 0;
		ulint			longest_i	= ULINT_MAX;
		byte*			data;
		big_rec_field_t*	b;

		for (i = dict_index_get_n_unique_in_tree(index);
		     i < dtuple_get_n_fields(entry); i++) {
			ulint	savings;

			dfield = dtuple_get_nth_field(entry, i);
			ifield = dict_index_get_nth_field(index, i);

			/* Skip fixed-length, NULL, externally stored,
			or short columns */

			if (ifield->fixed_len
			    || dfield_is_null(dfield)
			    || dfield_is_ext(dfield)
			    || dfield_get_len(dfield) <= local_len
			    || dfield_get_len(dfield)
			    <= BTR_EXTERN_FIELD_REF_SIZE * 2) {
				goto skip_field;
			}

			savings = dfield_get_len(dfield) - local_len;

			/* Check that there would be savings */
			if (longest >= savings) {
				goto skip_field;
			}

			longest_i = i;
			longest = savings;

skip_field:
			continue;
		}

		if (!longest) {
			/* Cannot shorten more */

			mem_heap_free(heap);

			return(NULL);
		}

		/* Move data from field longest_i to big rec vector.

		We store the first bytes locally to the record. Then
		we can calculate all ordering fields in all indexes
		from locally stored data. */

		dfield = dtuple_get_nth_field(entry, longest_i);
		ifield = dict_index_get_nth_field(index, longest_i);
		local_prefix_len = local_len - BTR_EXTERN_FIELD_REF_SIZE;

		b = &vector->fields[n_fields];
		b->field_no = longest_i;
		b->len = dfield_get_len(dfield) - local_prefix_len;
		b->data = (char*) dfield_get_data(dfield) + local_prefix_len;

		/* Allocate the locally stored part of the column. */
		data = mem_heap_alloc(heap, local_len);

		/* Copy the local prefix. */
		memcpy(data, dfield_get_data(dfield), local_prefix_len);
		/* Clear the extern field reference (BLOB pointer). */
		memset(data + local_prefix_len, 0, BTR_EXTERN_FIELD_REF_SIZE);
#if 0
		/* The following would fail the Valgrind checks in
		page_cur_insert_rec_low() and page_cur_insert_rec_zip().
		The BLOB pointers in the record will be initialized after
		the record and the BLOBs have been written. */
		UNIV_MEM_ALLOC(data + local_prefix_len,
			       BTR_EXTERN_FIELD_REF_SIZE);
#endif

		dfield_set_data(dfield, data, local_len);
		dfield_set_ext(dfield);

		n_fields++;
		(*n_ext)++;
		ut_ad(n_fields < dtuple_get_n_fields(entry));
	}

	vector->n_fields = n_fields;
	return(vector);
}

dtuple_t*
row_build_row_ref(
/*==============*/
				/* out, own: row reference built; see the
				NOTE below! */
	ulint		type,	/* in: ROW_COPY_DATA, or ROW_COPY_POINTERS:
				the former copies also the data fields to
				heap, whereas the latter only places pointers
				to data fields on the index page */
	dict_index_t*	index,	/* in: index */
	rec_t*		rec,	/* in: record in the index;
				NOTE: in the case ROW_COPY_POINTERS
				the data fields in the row will point
				directly into this record, therefore,
				the buffer page of this record must be
				at least s-latched and the latch held
				as long as the row reference is used! */
	mem_heap_t*	heap)	/* in: memory heap from which the memory
				needed is allocated */
{
	dict_table_t*	table;
	dict_index_t*	clust_index;
	dfield_t*	dfield;
	dtuple_t*	ref;
	byte*		field;
	ulint		len;
	ulint		ref_len;
	ulint		pos;
	byte*		buf;
	ulint		i;
	
	ut_ad(index && rec && heap);
	
	if (type == ROW_COPY_DATA) {
		/* Take a copy of rec to heap */

		buf = mem_heap_alloc(heap, rec_get_size(rec));

		rec = rec_copy(buf, rec);
	}

	table = index->table;
	
	clust_index = dict_table_get_first_index(table);

	ref_len = dict_index_get_n_unique(clust_index);

	ref = dtuple_create(heap, ref_len);

	dict_index_copy_types(ref, clust_index, ref_len);

	for (i = 0; i < ref_len; i++) {
		dfield = dtuple_get_nth_field(ref, i);

		pos = dict_index_get_nth_field_pos(index, clust_index, i);

		ut_a(pos != ULINT_UNDEFINED);
	
		field = rec_get_nth_field(rec, pos, &len);

		dfield_set_data(dfield, field, len);
	}

	ut_ad(dtuple_check_typed(ref));

	return(ref);
}

/*********************************************************************
Based on a table object, this function builds the entry to be inserted
in the SYS_COLUMNS system table. */
static
dtuple_t*
dict_create_sys_columns_tuple(
/*==========================*/
				/* out: the tuple which should be inserted */
	dict_table_t*	table,	/* in: table */
	ulint		i,	/* in: column number */
	mem_heap_t*	heap)	/* in: memory heap from which the memory for
				the built tuple is allocated */
{
	dict_table_t*		sys_columns;
	dtuple_t*		entry;
	const dict_col_t*	column;
	dfield_t*		dfield;
	byte*			ptr;
	const char*	col_name;

	ut_ad(table && heap);

	column = dict_table_get_nth_col(table, i);

	sys_columns = dict_sys->sys_columns;

	entry = dtuple_create(heap, 7 + DATA_N_SYS_COLS);

	/* 0: TABLE_ID -----------------------*/
	dfield = dtuple_get_nth_field(entry, 0);

	ptr = mem_heap_alloc(heap, 8);
	mach_write_to_8(ptr, table->id);

	dfield_set_data(dfield, ptr, 8);
	/* 1: POS ----------------------------*/
	dfield = dtuple_get_nth_field(entry, 1);

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, i);

	dfield_set_data(dfield, ptr, 4);
	/* 4: NAME ---------------------------*/
	dfield = dtuple_get_nth_field(entry, 2);

	col_name = dict_table_get_col_name(table, i);
	dfield_set_data(dfield, col_name, ut_strlen(col_name));
	/* 5: MTYPE --------------------------*/
	dfield = dtuple_get_nth_field(entry, 3);

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, column->mtype);

	dfield_set_data(dfield, ptr, 4);
	/* 6: PRTYPE -------------------------*/
	dfield = dtuple_get_nth_field(entry, 4);

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, column->prtype);

	dfield_set_data(dfield, ptr, 4);
	/* 7: LEN ----------------------------*/
	dfield = dtuple_get_nth_field(entry, 5);

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, column->len);

	dfield_set_data(dfield, ptr, 4);
	/* 8: PREC ---------------------------*/
	dfield = dtuple_get_nth_field(entry, 6);

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, 0/* unused */);

	dfield_set_data(dfield, ptr, 4);
	/*---------------------------------*/

	dict_table_copy_types(entry, sys_columns);

	return(entry);
}

/*********************************************************************
Based on a table object, this function builds the entry to be inserted
in the SYS_TABLES system table. */
static
dtuple_t*
dict_create_sys_tables_tuple(
/*=========================*/
				/* out: the tuple which should be inserted */
	dict_table_t*	table,	/* in: table */
	mem_heap_t*	heap)	/* in: memory heap from which the memory for
				the built tuple is allocated */
{
	dict_table_t*	sys_tables;
	dtuple_t*	entry;
	dfield_t*	dfield;
	byte*		ptr;

	ut_ad(table && heap);

	sys_tables = dict_sys->sys_tables;

	entry = dtuple_create(heap, 8 + DATA_N_SYS_COLS);

	/* 0: NAME -----------------------------*/
	dfield = dtuple_get_nth_field(entry, 0);

	dfield_set_data(dfield, table->name, ut_strlen(table->name));
	/* 3: ID -------------------------------*/
	dfield = dtuple_get_nth_field(entry, 1);

	ptr = mem_heap_alloc(heap, 8);
	mach_write_to_8(ptr, table->id);

	dfield_set_data(dfield, ptr, 8);
	/* 4: N_COLS ---------------------------*/
	dfield = dtuple_get_nth_field(entry, 2);

#if DICT_TF_COMPACT != 1
#error
#endif

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, table->n_def
			| ((table->flags & DICT_TF_COMPACT) << 31));
	dfield_set_data(dfield, ptr, 4);
	/* 5: TYPE -----------------------------*/
	dfield = dtuple_get_nth_field(entry, 3);

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, DICT_TABLE_ORDINARY);

	dfield_set_data(dfield, ptr, 4);
	/* 6: MIX_ID (obsolete) ---------------------------*/
	dfield = dtuple_get_nth_field(entry, 4);

	ptr = mem_heap_alloc(heap, 8);
	memset(ptr, 0, 8);

	dfield_set_data(dfield, ptr, 8);
	/* 7: MIX_LEN (obsolete) --------------------------*/

	dfield = dtuple_get_nth_field(entry, 5);

	ptr = mem_heap_alloc(heap, 4);
	memset(ptr, 0, 4);

	dfield_set_data(dfield, ptr, 4);
	/* 8: CLUSTER_NAME ---------------------*/
	dfield = dtuple_get_nth_field(entry, 6);
	dfield_set_data(dfield, NULL, UNIV_SQL_NULL); /* not supported */

	/* 9: SPACE ----------------------------*/
	dfield = dtuple_get_nth_field(entry, 7);

	ptr = mem_heap_alloc(heap, 4);
	mach_write_to_4(ptr, table->space);

	dfield_set_data(dfield, ptr, 4);
	/*----------------------------------*/

	dict_table_copy_types(entry, sys_tables);

	return(entry);
}

//.........这里部分代码省略.........
	} else {
		ut_ad(rec_offs_validate(rec, index, offsets));
	}

#if defined UNIV_DEBUG || defined UNIV_BLOB_LIGHT_DEBUG
	if (rec_offs_any_null_extern(rec, offsets)) {
		/* This condition can occur during crash recovery
		before trx_rollback_active() has completed execution,
		or when a concurrently executing
		row_ins_index_entry_low() has committed the B-tree
		mini-transaction but has not yet managed to restore
		the cursor position for writing the big_rec. */
		ut_a(trx_undo_roll_ptr_is_insert(
			     row_get_rec_roll_ptr(rec, index, offsets)));
	}
#endif /* UNIV_DEBUG || UNIV_BLOB_LIGHT_DEBUG */

	if (type != ROW_COPY_POINTERS) {
		/* Take a copy of rec to heap */
		buf = mem_heap_alloc(heap, rec_offs_size(offsets));
		rec = rec_copy(buf, rec, offsets);
		/* Avoid a debug assertion in rec_offs_validate(). */
		rec_offs_make_valid(rec, index, (ulint*) offsets);
	}

	table = index->table;
	row_len = dict_table_get_n_cols(table);

	row = dtuple_create(heap, row_len);

	dict_table_copy_types(row, table);

	dtuple_set_info_bits(row, rec_get_info_bits(
				     rec, dict_table_is_comp(table)));

	n_fields = rec_offs_n_fields(offsets);
	n_ext_cols = rec_offs_n_extern(offsets);
	if (n_ext_cols) {
		ext_cols = mem_heap_alloc(heap, n_ext_cols * sizeof *ext_cols);
	}

	for (i = j = 0; i < n_fields; i++) {
		dict_field_t*		ind_field
			= dict_index_get_nth_field(index, i);
		const dict_col_t*	col
			= dict_field_get_col(ind_field);
		ulint			col_no
			= dict_col_get_no(col);
		dfield_t*		dfield
			= dtuple_get_nth_field(row, col_no);

		if (ind_field->prefix_len == 0) {

			const byte*	field = rec_get_nth_field(
				rec, offsets, i, &len);

			dfield_set_data(dfield, field, len);
		}

		if (rec_offs_nth_extern(offsets, i)) {
			dfield_set_ext(dfield);

			if (UNIV_LIKELY_NULL(col_table)) {
				ut_a(col_no
				     < dict_table_get_n_cols(col_table));
				col = dict_table_get_nth_col(
					col_table, col_no);
			}

			if (col->ord_part) {
				/* We will have to fetch prefixes of
				externally stored columns that are
				referenced by column prefixes. */
				ext_cols[j++] = col_no;
			}
		}
	}

	ut_ad(dtuple_check_typed(row));

	if (!ext) {
		/* REDUNDANT and COMPACT formats store a local
		768-byte prefix of each externally stored
		column. No cache is needed. */
		ut_ad(dict_table_get_format(index->table)
		      < DICT_TF_FORMAT_ZIP);
	} else if (j) {
		*ext = row_ext_create(j, ext_cols, row,
				      dict_table_zip_size(index->table),
				      heap);
	} else {
		*ext = NULL;
	}

	if (tmp_heap) {
		mem_heap_free(tmp_heap);
	}

	return(row);
}

ulint
dict_load_foreigns(
/*===============*/
				/* out: DB_SUCCESS or error code */
	char*	table_name)	/* in: table name */
{
	btr_pcur_t	pcur;
	mem_heap_t* 	heap;
	dtuple_t*	tuple;
	dfield_t*	dfield;
	dict_index_t*	sec_index;
	dict_table_t*	sys_foreign;
	rec_t*		rec;
	byte*		field;
	ulint		len;	
	char*		id ;
	ulint		err;
	mtr_t		mtr;
	
	ut_ad(mutex_own(&(dict_sys->mutex)));

	sys_foreign = dict_table_get_low("SYS_FOREIGN");

	if (sys_foreign == NULL) {
		/* No foreign keys defined yet in this database */

		fprintf(stderr,
	"InnoDB: Error: no foreign key system tables in the database\n");
		
		return(DB_ERROR);
	}

	mtr_start(&mtr);	

	/* Get the secondary index based on FOR_NAME from table
	SYS_FOREIGN */	

	sec_index = dict_table_get_next_index(
				dict_table_get_first_index(sys_foreign));
start_load:
	heap = mem_heap_create(256);

	tuple  = dtuple_create(heap, 1);
	dfield = dtuple_get_nth_field(tuple, 0);

	dfield_set_data(dfield, table_name, ut_strlen(table_name));
	dict_index_copy_types(tuple, sec_index, 1);

	btr_pcur_open_on_user_rec(sec_index, tuple, PAGE_CUR_GE,
						BTR_SEARCH_LEAF, &pcur, &mtr);
loop:
	rec = btr_pcur_get_rec(&pcur);
	
	if (!btr_pcur_is_on_user_rec(&pcur, &mtr)) {
		/* End of index */

		goto load_next_index;
	}

	/* Now we have the record in the secondary index containing a table
	name and a foreign constraint ID */

	rec = btr_pcur_get_rec(&pcur);
	field = rec_get_nth_field(rec, 0, &len);

	/* Check if the table name in record is the one searched for */
	if (len != ut_strlen(table_name)
	    || 0 != ut_memcmp(field, table_name, len)) {

		goto load_next_index;
	}
		
	if (rec_get_deleted_flag(rec)) {

		goto next_rec;
	}

	/* Now we get a foreign key constraint id */
	field = rec_get_nth_field(rec, 1, &len);

	id = mem_heap_alloc(heap, len + 1);
	ut_memcpy(id, field, len);
	id[len] = '\0';
	
	btr_pcur_store_position(&pcur, &mtr);

	mtr_commit(&mtr);

	/* Load the foreign constraint definition to the dictionary cache */
	
	err = dict_load_foreign(id);

	if (err != DB_SUCCESS) {
		btr_pcur_close(&pcur);
		mem_heap_free(heap);

		return(err);
	}

	mtr_start(&mtr);
//.........这里部分代码省略.........

/*****************************************************************//**
Based on a table object, this function builds the entry to be inserted
in the SYS_TABLES system table.
@return	the tuple which should be inserted */
static
dtuple_t*
dict_create_sys_tables_tuple(
    /*=========================*/
    const dict_table_t*	table,	/*!< in: table */
    mem_heap_t*		heap)	/*!< in: memory heap from
					which the memory for the built
					tuple is allocated */
{
    dict_table_t*	sys_tables;
    dtuple_t*	entry;
    dfield_t*	dfield;
    byte*		ptr;

    ut_ad(table);
    ut_ad(heap);

    sys_tables = dict_sys->sys_tables;

    entry = dtuple_create(heap, 8 + DATA_N_SYS_COLS);

    dict_table_copy_types(entry, sys_tables);

    /* 0: NAME -----------------------------*/
    dfield = dtuple_get_nth_field(entry, 0/*NAME*/);

    dfield_set_data(dfield, table->name, ut_strlen(table->name));
    /* 3: ID -------------------------------*/
    dfield = dtuple_get_nth_field(entry, 1/*ID*/);

    ptr = mem_heap_alloc(heap, 8);
    mach_write_to_8(ptr, table->id);

    dfield_set_data(dfield, ptr, 8);
    /* 4: N_COLS ---------------------------*/
    dfield = dtuple_get_nth_field(entry, 2/*N_COLS*/);

#if DICT_TF_COMPACT != 1
#error
#endif

    ptr = mem_heap_alloc(heap, 4);
    if (dict_table_is_gcs(table))                       /* ±í¶¨ÒåÐÞ¸Ä */
    {
        ut_ad(dict_table_is_comp(table));

        mach_write_to_4(ptr, table->n_def
                        | (1 << 31) | (1 << 30));
    }
    else
    {
        mach_write_to_4(ptr, table->n_def
                        | ((table->flags & DICT_TF_COMPACT) << 31));
    }

    dfield_set_data(dfield, ptr, 4);
    /* 5: TYPE -----------------------------*/
    dfield = dtuple_get_nth_field(entry, 3/*TYPE*/);

    ptr = mem_heap_alloc(heap, 4);
    if (table->flags & (~DICT_TF_COMPACT & ~(~0 << DICT_TF_BITS))) {
        ut_a(table->flags & DICT_TF_COMPACT);
        ut_a(dict_table_get_format(table) >= DICT_TF_FORMAT_ZIP);
        ut_a((table->flags & DICT_TF_ZSSIZE_MASK)
             <= (DICT_TF_ZSSIZE_MAX << DICT_TF_ZSSIZE_SHIFT));
        ut_a(!(table->flags & (~0 << DICT_TF2_BITS)));
        mach_write_to_4(ptr, table->flags & ~(~0 << DICT_TF_BITS));
    } else {
        mach_write_to_4(ptr, DICT_TABLE_ORDINARY);
    }

    dfield_set_data(dfield, ptr, 4);
    /* 6: MIX_ID (obsolete) ---------------------------*/
    dfield = dtuple_get_nth_field(entry, 4/*MIX_ID*/);

    ptr = mem_heap_zalloc(heap, 8);

    dfield_set_data(dfield, ptr, 8);
    /* 7: MIX_LEN (additional flags) --------------------------*/

    dfield = dtuple_get_nth_field(entry, 5/*MIX_LEN*/);

    ptr = mem_heap_alloc(heap, 4);
    mach_write_to_4(ptr, table->flags >> DICT_TF2_SHIFT);

    ut_ad(table->n_cols_before_alter_table == 0);

    dfield_set_data(dfield, ptr, 4);
    /* 8: CLUSTER_NAME ---------------------*/
    dfield = dtuple_get_nth_field(entry, 6/*CLUSTER_NAME*/);
    dfield_set_null(dfield); /* not supported */

    /* 9: SPACE ----------------------------*/
    dfield = dtuple_get_nth_field(entry, 7/*SPACE*/);

    ptr = mem_heap_alloc(heap, 4);
//.........这里部分代码省略.........

dtuple_t*
row_build(
/*======*/
				/* out, own: row built; see the NOTE below! */
	ulint		type,	/* in: ROW_COPY_POINTERS, ROW_COPY_DATA, or
				ROW_COPY_ALSO_EXTERNALS, 
				the two last copy also the data fields to
				heap as the first only places pointers to
				data fields on the index page, and thus is
				more efficient */
	dict_index_t*	index,	/* in: clustered index */
	rec_t*		rec,	/* in: record in the clustered index;
				NOTE: in the case ROW_COPY_POINTERS
				the data fields in the row will point
				directly into this record, therefore,
				the buffer page of this record must be
				at least s-latched and the latch held
				as long as the row dtuple is used! */
	mem_heap_t*	heap)	/* in: memory heap from which the memory
				needed is allocated */
{
	dtuple_t*	row;
	dict_table_t*	table;
	dict_field_t*	ind_field;
	dict_col_t*	col;
	dfield_t*	dfield;
	ulint		n_fields;
	byte*		field;
	ulint		len;
	ulint		row_len;
	byte*		buf; 
	ulint		i;
	
	ut_ad(index && rec && heap);
	ut_ad(index->type & DICT_CLUSTERED);

	if (type != ROW_COPY_POINTERS) {
		/* Take a copy of rec to heap */
		buf = mem_heap_alloc(heap, rec_get_size(rec));
		rec = rec_copy(buf, rec);
	}

	table = index->table;
	row_len = dict_table_get_n_cols(table);

	row = dtuple_create(heap, row_len);

	dtuple_set_info_bits(row, rec_get_info_bits(rec));
	
	n_fields = dict_index_get_n_fields(index);

	ut_ad(n_fields == rec_get_n_fields(rec));

	dict_table_copy_types(row, table);

	for (i = 0; i < n_fields; i++) {
	        ind_field = dict_index_get_nth_field(index, i);

		if (ind_field->prefix_len == 0) {

		        col = dict_field_get_col(ind_field);
			dfield = dtuple_get_nth_field(row,
						dict_col_get_no(col));
			field = rec_get_nth_field(rec, i, &len);

			if (type == ROW_COPY_ALSO_EXTERNALS
			    && rec_get_nth_field_extern_bit(rec, i)) {

			        field = btr_rec_copy_externally_stored_field(
							rec, i, &len, heap);
			}

			dfield_set_data(dfield, field, len);
		}
	}

	ut_ad(dtuple_check_typed(row));

	return(row);
}

void
row_build_row_ref_in_tuple(
/*=======================*/
	dtuple_t*	ref,	/* in/out: row reference built; see the
				NOTE below! */
	dict_index_t*	index,	/* in: index */
	rec_t*		rec)	/* in: record in the index;
				NOTE: the data fields in ref will point
				directly into this record, therefore,
				the buffer page of this record must be
				at least s-latched and the latch held
				as long as the row reference is used! */
{
	dict_table_t*	table;
	dict_index_t*	clust_index;
	dfield_t*	dfield;
	byte*		field;
	ulint		len;
	ulint		ref_len;
	ulint		pos;
	ulint		i;
	
	ut_a(ref && index && rec);
	
	table = index->table;

	if (!table) {
		fprintf(stderr, "InnoDB: table %s for index %s not found\n",
				index->table_name, index->name);
		ut_a(0);
	}
	
	clust_index = dict_table_get_first_index(table);
	
	if (!clust_index) {
		fprintf(stderr,
                "InnoDB: clust index for table %s for index %s not found\n",
				index->table_name, index->name);
		ut_a(0);
	}
	
	ref_len = dict_index_get_n_unique(clust_index);

	ut_ad(ref_len == dtuple_get_n_fields(ref));
	
	dict_index_copy_types(ref, clust_index, ref_len);

	for (i = 0; i < ref_len; i++) {
		dfield = dtuple_get_nth_field(ref, i);

		pos = dict_index_get_nth_field_pos(index, clust_index, i);

		ut_a(pos != ULINT_UNDEFINED);
			
		field = rec_get_nth_field(rec, pos, &len);

		dfield_set_data(dfield, field, len);
	}

	ut_ad(dtuple_check_typed(ref));
}