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drizzled/join_table.cc
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 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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 */
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#include <config.h>
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#include "config.h"
 
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#include <drizzled/join_table.h>
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#include <drizzled/field/blob.h>
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#include <drizzled/join_table.h>
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#include <drizzled/sql_lex.h>
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#include <drizzled/sql_select.h>
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#include <drizzled/table.h>
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#include <drizzled/util/test.h>
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namespace drizzled
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{
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int JoinTable::joinReadConstTable(optimizer::Position *pos)
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{
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  int error;
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  Table *Table= this->table;
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  Table->const_table=1;
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  Table->null_row=0;
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  Table->status=STATUS_NO_RECORD;
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  if (this->type == AM_SYSTEM)
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  {
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    if ((error=this->joinReadSystem()))
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    {                                           // Info for DESCRIBE
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      this->info="const row not found";
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      /* Mark for EXPLAIN that the row was not found */
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      pos->setFanout(0.0);
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      pos->clearRefDependMap();
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      if (! Table->maybe_null || error > 0)
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        return(error);
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    }
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  }
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  else
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  {
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    if (! Table->key_read && 
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        Table->covering_keys.test(this->ref.key) && 
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        ! Table->no_keyread &&
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        (int) Table->reginfo.lock_type <= (int) TL_READ_WITH_SHARED_LOCKS)
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    {
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      Table->key_read=1;
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      Table->cursor->extra(HA_EXTRA_KEYREAD);
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      this->index= this->ref.key;
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    }
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    error=join_read_const(this);
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    if (Table->key_read)
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    {
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      Table->key_read=0;
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      Table->cursor->extra(HA_EXTRA_NO_KEYREAD);
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    }
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    if (error)
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    {
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      this->info="unique row not found";
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      /* Mark for EXPLAIN that the row was not found */
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      pos->setFanout(0.0);
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      pos->clearRefDependMap();
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      if (!Table->maybe_null || error > 0)
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        return(error);
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    }
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  }
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  if (*this->on_expr_ref && !Table->null_row)
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  {
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    if ((Table->null_row= test((*this->on_expr_ref)->val_int() == 0)))
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      Table->mark_as_null_row();
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  }
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  if (!Table->null_row)
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    Table->maybe_null=0;
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  /* Check appearance of new constant items in Item_equal objects */
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  Join *Join= this->join;
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  if (Join->conds)
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    update_const_equal_items(Join->conds, this);
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  TableList *tbl;
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  for (tbl= Join->select_lex->leaf_tables; tbl; tbl= tbl->next_leaf)
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  {
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    TableList *embedded;
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    TableList *embedding= tbl;
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    do
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    {
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      embedded= embedding;
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      if (embedded->on_expr)
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         update_const_equal_items(embedded->on_expr, this);
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      embedding= embedded->getEmbedding();
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    }
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    while (embedding &&
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           embedding->getNestedJoin()->join_list.head() == embedded);
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  }
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  return(0);
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}
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void JoinTable::readCachedRecord()
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{
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  unsigned char *pos;
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  this->cache.pos=pos;
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}
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int JoinTable::joinReadSystem()
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{
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  Table *Table= this->table;
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  int error;
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  if (Table->status & STATUS_GARBAGE)           // If first read
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  {
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    if ((error=Table->cursor->read_first_row(table->getInsertRecord(),
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                                           Table->getShare()->getPrimaryKey())))
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    {
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      if (error != HA_ERR_END_OF_FILE)
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        return Table->report_error(error);
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      this->table->mark_as_null_row();
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      Table->emptyRecord();                     // Make empty record
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      return -1;
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    }
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    Table->storeRecord();
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  }
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  else if (!Table->status)                      // Only happens with left join
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    Table->restoreRecord();                     // restore old record
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  Table->null_row=0;
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  return Table->status ? -1 : 0;
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}
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} /* namespace drizzled */