drop a column index
@param string|array $name
355597
public function dropIndex($name)
    {
        if (is_array($name))
            $name = $this->name.'___'.implode('__', $name);
        elseif(!is_int(strpos($name,'___')))
            $name = $this->name.'___'.$name;
        $name = $this->db->quotekey($name);
        $table = $this->db->quotekey($this->name);
        $cmd = array(
            'pgsql|sqlite2?|ibm' =>
                "DROP INDEX $name;",
            'mssql|sybase|dblib|odbc|sqlsrv' =>
                "DROP INDEX $table.$name;",
            'mysql'=>
                "ALTER TABLE $table DROP INDEX $name;",
        );
        $query = $this->findQuery($cmd);
        $this->queries[] = $query;
    }
442609
public static function deleteColumn(string $tableName, string $column)
    {
        if(Schema::hasTable($tableName)) {
            Schema::table(
                $tableName, function ($table) use ($tableName, $column) {
                    if(Schema::hasColumn($tableName, $column)) {
                        $table->dropColumn($column);
                    }
                }
            );
        }
    }
56970
public function dropColumn($name)
    {
        $colTypes = $this->getCols(true);
        // check if column exists
        if (!in_array($name, array_keys($colTypes))) return true;
        if (preg_match('/sqlite2?/', $this->db->driver())) {
            // SQlite does not support drop column directly
            $this->rebuild_cmd['drop'][] = $name;
        } else {
            $quotedTable = $this->db->quotekey($this->name);
            $quotedColumn = $this->db->quotekey($name);
            $cmd = array(
                'mysql' =>
                    "ALTER TABLE $quotedTable DROP $quotedColumn;",
                'pgsql|odbc|ibm|mssql|sybase|dblib|sqlsrv' =>
                    "ALTER TABLE $quotedTable DROP COLUMN $quotedColumn;",
            );
            if (preg_match('/mssql|sybase|dblib|sqlsrv/', $this->db->driver()))
                $this->suppress=true;
            $this->queries[] = $this->findQuery($cmd);
        }
    }
565532
public function dropIndex($name, $table = null)
    {
        return $this->db->dropIndex($table, $name)
                        ->execute();
    }
829502
public function remove($name)
    {
        if (isset($this->aliasIndex[$name])) {
            $this->remove($this->aliasIndex[$name]);

            return;
        }

        if (isset($this->shortNameIndex[$name])) {
            $this->remove($this->shortNameIndex[$name]);

            return;
        }

        unset($this->commands[$name]);

        foreach ($this->shortNameIndex as $shortName => $targetName) {
            if ($name === $targetName) {
                unset($this->shortNameIndex[$shortName]);
            }
        }

        foreach ($this->aliasIndex as $alias => $targetName) {
            if ($name === $targetName) {
                unset($this->aliasIndex[$alias]);
            }
        }
    }
665172
public function dropCheck($name)
    {
        if (!$this->hasCheck($name)) {
            throw SchemaException::tableCheckDoesNotExist($this->getName(), $name);
        }

        unset($this->checks[$name]);
    }
1126346
protected function dropColumn(string $tableName, string $column) : void
    {
        // Check for its existence before dropping
        if (! $this->schema->hasColumn($tableName, $column)) {
            return;
        }

        $this->schema->table($tableName, function (Blueprint $table) use ($column) {
            $table->dropColumn($column);
        });
    }
382028
public function DropColumn($Name) {
      if (!$this->Query('alter table `'.$this->_DatabasePrefix.$this->_TableName.'` drop column `'.$Name.'`'))
         throw new Exception(sprintf(T('Failed to remove the `%1$s` column from the `%2$s` table.'), $Name, $this->_DatabasePrefix.$this->_TableName));

      return TRUE;
   }
412396
public function removeHeader($name) {
        if (true === array_key_exists($name, $this->headers)) {
            unset($this->headers[$name]);
        }
    }
163951
private function dropColumnOnSqlite($name)
    {
        $pdo = Database::getPdo();

        $names = (array) $name;

        $statement = $pdo->query(sprintf('PRAGMA table_info(%s);', $this->table));

        $statement->execute();

        $sql = [];

        foreach ($statement->fetchAll() as $column) {
            if (!in_array($column->name, $names)) {
                $select[] = $column->name;
            }
        }

        $pdo->exec('BEGIN TRANSACTION;');

        $pdo->exec(sprintf(
            'CREATE TABLE __temp_sqlite_table AS SELECT %s FROM %s;',
            implode(', ', $select),
            $this->table
        ));

        $pdo->exec(sprintf('DROP TABLE %s;', $this->table));

        $pdo->exec(sprintf('ALTER TABLE __temp_sqlite_table RENAME TO %s;', $this->table));

        $pdo->exec('COMMIT;');
    }
550792
public function removeTick($name)
    {
        if (isset($this->ticks[$name])) {
            $this->ticks[$name]->setManager(null);
            unset($this->ticks[$name]);
        }
    }
1186421
public function dropColumn($name)
    {
        if ($this->adapter == 'mysql') {
            $this->dropColumnOnMysql($name);
        } else {
            $this->dropColumnOnSqlite($name);
        }

        return $this;
    }
991451
public function offsetUnset($name)
	{
		$component = $this->getComponent($name, FALSE);
		if ($component !== NULL) {
			$this->removeComponent($component);
		}
	}
149525
protected function unsetReadonlyProperty(string $name): void
    {
        if ($this->issetReadonlyProperty($name)) {
            unset($this->readonlyValues[$name]);
        }
    }
1294133
public function dropColumn($columns)
    {
        $columns = is_array($columns) ? $columns : func_get_args();

        return $this->addCommand('dropColumn', compact('columns'));
    }
526047
final public function findIndexColumnByName(string $name): ? IndexColumn
    {
        /** @var IndexColumn $indexColumn */
        foreach ($this->columns as $indexColumn) {
            $column = $indexColumn->getColumn();
            if ($column::getName() === $name) {
                return $indexColumn;
            }
        }

        return null;
    }
280136
function disable(string $name) {
        $pos = array_search($name, $this->_enableList);
        if ($pos === false)
            return;
        unset($this->_enableList[$pos]);
    }