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Is this an example of a fluent interface?

Bruce Gust
Bruce Gust asked
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Last Modified: 2014-11-25
I have a Class that has within it two methods. The first method grabs an ID that's arriving from a form and, via a select statement, retrieves the name of the table that corresponds to that ID.

The next method's job is to retrieve the column names of the table the previous method has ascertained.

It looks like this:

class TableData {

	public $table_name;

	function TableName()
	{
		global $mysqli;

		$sql="select table_name from tools where id='$_POST[table_id]'";
			if(!$query=$mysqli->query($sql))
			{
				$err=$mysqli->errno.': '.$mysqli->error;
				trigger_error($err, E_USER_WARNING);
			}
		$row=$query->fetch_object();
		$the_name=$row->tool_name;
		
		$this->table_name=$the_name;
	}

	function TableInfo()
	{
		global $mysqli;
		
		$sql = "show columns from $table_name";
		$query = $mysqli->query($sql);
		
		if(!$query)
		{
		$error = $mysqli->errno.': '.$mysqli->error;
		trigger_error($error, E_USER_WARNING);
		}
		
		$data_count=mysqli_num_rows($query);
		
		if($data_count==0)
		{
		trigger_error("you don't have any column names", E_USER_WARNING);
		}
		//return $data_count;
		
		while($show_columns=$query->fetch_object())
		{
		$the_columns[]=$show_columns->Field;
		}
		return $the_columns;
	}
}

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I imagine you could retrieve the name of the table and then pass it on as a variable into a subsequent function, but I'm thinking there's a more elegant way to do this. As I was looking for some answers I stumbled upon the term "fluent interface" and I'm not sure if that's what I'm looking for, but there it is.

Can I set in motion a "daisy chain" of methods by instantiating one Class? If so, how. If not, what are my options in terms of sound programming?
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Bruce GustPHP Developer

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Commented:
Kaufmed - thanks for getting back with me!

I had already seen the example you referenced on the Wiki page. Thing is, I couldn't figure out how to do it in the context of my scenario.

Going back to that for a moment, I was able to get it to work. Here's my Class:

class TableData {

	public $table_name;

	function TableName()
	{
		global $mysqli;

		$sql="select table_name from tools where id='$_POST[table_id]'";
		if(!$query=$mysqli->query($sql))
			{
				$err=$mysqli->errno.': '.$mysqli->error;
				trigger_error($err, E_USER_WARNING);
			}
		$row=$query->fetch_object();
		$the_name=$row->table_name;
		
		return $the_name;
	}

	function TableInfo($table_name)
	{
		global $mysqli;
		
		$sql = "show columns from $table_name";
		echo $sql;
		$query = $mysqli->query($sql);
		
		if(!$query)
		{
		$error = $mysqli->errno.': '.$mysqli->error;
		trigger_error($error, E_USER_WARNING);
		}
		
		$data_count=mysqli_num_rows($query);
		
		if($data_count==0)
		{
		trigger_error("you don't have any column names", E_USER_WARNING);
		}
		//return $data_count;
		
		while($show_columns=$query->fetch_object())
		{
		$the_columns[]=$show_columns->Field;
		}
		return $the_columns;
	}
}

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And then here's what I instantiated things so I could get my needed result:

$table_stuff=new TableData;
$table_handle=$table_stuff->TableName();
$columns = $table_stuff->TableInfo($table_handle);

It works! But if I were looking to something a little more elegant / streamlined and I wanted one call, one Class and one result, how would that look? Can that be done?
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Commented:
Notice that the first call, FetchTableName, returns the object itself, not any data. Only the last call in the chain returns something other than the object itself.
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