diff options
Diffstat (limited to 'sql/sql_update.cc')
| -rw-r--r-- | sql/sql_update.cc | 51 |
1 files changed, 30 insertions, 21 deletions
diff --git a/sql/sql_update.cc b/sql/sql_update.cc index 5108c991aba..b4216adc2cd 100644 --- a/sql/sql_update.cc +++ b/sql/sql_update.cc @@ -16,9 +16,7 @@ /* Update of records - Multi-table updates were introduced by Monty and Sinisa <sinisa@mysql.com> - */ #include "mysql_priv.h" @@ -347,7 +345,7 @@ int mysql_update(THD *thd, } /*************************************************************************** -** update multiple tables from join + Update multiple tables from join ***************************************************************************/ multi_update::multi_update(THD *thd_arg, TABLE_LIST *ut, List<Item> &fs, @@ -363,7 +361,7 @@ multi_update::multi_update(THD *thd_arg, TABLE_LIST *ut, List<Item> &fs, for (TABLE_LIST *dt=ut ; dt ; dt=dt->next,counter++) { TABLE *table=ut->table; -// (void) ut->table->file->extra(HA_EXTRA_NO_KEYREAD); + // (void) ut->table->file->extra(HA_EXTRA_NO_KEYREAD); dt->table->used_keys=0; if (table->timestamp_field) { @@ -402,10 +400,14 @@ multi_update::prepare(List<Item> &values) } } } -// Here I have to connect fields with tables and only update tables that need to be updated ... + /* + Here I have to connect fields with tables and only update tables that + need to be updated. + I calculate num_updated and fill-up table_sequence + Set table_list->shared to true or false, depending on whether table is + to be updated or not + */ -// I calculate num_updated and fill-up table_sequence -// Set table_list->shared to true or false, depending on whether table is to be updated or not Item_field *item; List_iterator<Item> it(fields); num_fields=fields.elements; @@ -414,7 +416,8 @@ multi_update::prepare(List<Item> &values) while ((item= (Item_field *)it++)) { unsigned int counter=0; - for (table_ref=update_tables; table_ref; table_ref=table_ref->next, counter++) + for (table_ref=update_tables; table_ref; + table_ref=table_ref->next, counter++) { if (table_ref->table == item->field->table && !table_ref->shared) { @@ -422,7 +425,8 @@ multi_update::prepare(List<Item> &values) table_ref->shared=1; if (!not_trans_safe && !table_ref->table->file->has_transactions()) not_trans_safe=true; - table_ref->table->no_keyread=1; // to be moved if initialize_tables has to be used + // to be moved if initialize_tables has to be used + table_ref->table->no_keyread=1; break; } } @@ -440,8 +444,10 @@ multi_update::prepare(List<Item> &values) DBUG_RETURN(1); } -// Here, I have to allocate the array of temporary tables -// I have to treat a case of num_updated=1 differently in send_data() method. + /* + Here, I have to allocate the array of temporary tables + I have to treat a case of num_updated=1 differently in send_data() method. + */ if (num_updated > 1) { tmp_tables = (TABLE **) sql_calloc(sizeof(TABLE *) * (num_updated - 1)); @@ -453,7 +459,7 @@ multi_update::prepare(List<Item> &values) { if (!table_ref->shared) continue; -// Here we have to add row offset as an additional field ... + // Here we have to add row offset as an additional field ... if (!(temp_fields = (List_item *)sql_calloc(sizeof(List_item)))) { error = 1; // A proper error message is due here @@ -470,13 +476,15 @@ multi_update::prepare(List<Item> &values) { Field_string offset(table_ref->table->file->ref_length,false,"offset",table_ref->table,true); temp_fields->push_front(new Item_field(((Field *)&offset))); -// Here I make tmp tables + // Here I make tmp tables int cnt=counter-1; TMP_TABLE_PARAM tmp_table_param; bzero((char*) &tmp_table_param,sizeof(tmp_table_param)); tmp_table_param.field_count=temp_fields->elements; - if (!(tmp_tables[cnt]=create_tmp_table(thd, &tmp_table_param, *temp_fields, - (ORDER*) 0, 1, 0, 0, TMP_TABLE_ALL_COLUMNS))) + if (!(tmp_tables[cnt]=create_tmp_table(thd, &tmp_table_param, + *temp_fields, + (ORDER*) 0, 1, 0, 0, + TMP_TABLE_ALL_COLUMNS))) { error = 1; // A proper error message is due here DBUG_RETURN(1); @@ -498,7 +506,8 @@ multi_update::prepare(List<Item> &values) void multi_update::initialize_tables(JOIN *join) { -/* We skip it as it only makes a mess ........... +/* + We skip it as it only makes a mess ........... TABLE_LIST *walk; table_map tables_to_update_from=0; for (walk= update_tables ; walk ; walk=walk->next) @@ -546,7 +555,7 @@ bool multi_update::send_data(List<Item> &values) List<Item> real_values(values); for (uint counter = 0; counter < fields.elements; counter++) real_values.pop(); -// We have skipped fields .... + // We have skipped fields .... if (num_updated == 1) { for (table_being_updated=update_tables ; @@ -560,7 +569,7 @@ bool multi_update::send_data(List<Item> &values) if (table->status & (STATUS_NULL_ROW | STATUS_UPDATED)) return 0; table->file->position(table->record[0]); -// Only one table being updated receives a completely different treatment + // Only one table being updated receives a completely different treatment table->status|= STATUS_UPDATED; store_record(table,1); if (fill_record(fields,real_values)) @@ -596,7 +605,7 @@ bool multi_update::send_data(List<Item> &values) if (*int_ptr++ == (uint) (secure_counter + 1)) values_by_table.push_back(item); } -// Here I am breaking values as per each table + // Here I am breaking values as per each table if (secure_counter < 0) { table->status|= STATUS_UPDATED; @@ -639,13 +648,13 @@ void multi_update::send_error(uint errcode,const char *err) ::send_error(&thd->net,errcode,err); /* reset used flags */ -// update_tables->table->no_keyread=0; + // update_tables->table->no_keyread=0; /* If nothing updated return */ if (!updated) return; - /* Somthing alredy updated consequently we have to invalidate cache */ + /* Something already updated so we have to invalidate cache */ query_cache_invalidate3(thd, update_tables, 1); /* Below can happen when thread is killed early ... */ |