relationship between tables

I have two tables with a column that has the same data, they are unique and are as if it were an id column, I connected these two columns to have a table with the data from both tables, the problem is this the parent table contains 10,000 rows while the child table contains 2,000 but I only see the data from the child table and I do not see those from the parent table, that is, I only see 2,000 results and instead I want to see all 10,000 results and if there is associated data in the child table see them if there is not see the empty columns, the relationship I created is this

public function modelcode()
    {
        return $this->belongsTo(Model::class, 'code_id', 'codeId')->withDefault(['codeId' => '']);
    }

and

->addColumn('codeId',function ($query) {
                return $query->modelcode->codeId;
            })

Column::make('codeId')->data('modelcode.codeId),

the values present in the parent table table1 are loaded, but only the total of the values of the child table table2 does not load everything, where am I going wrong?

jayandholariya

1 year ago

Best Answer

Level 4

@marcoplus For correct data retrieval, you need change the modelcode relationship to use hasOne rather than belongsTo.

When the current (parent) model owns a related record in the child model, hasOne is suitable.
belongsTo is used when the relationship's child is the current model, which isn't the case in this instance.

    public function modelcode() { 
        return $this->hasOne(ChildModel::class, 'codeId', 'code_id'); 
    }

Eagerly Loading Data Fetching:

    $data = ParentModel::with('modelcode')->get();

This guarantees that all parent records are obtained and, if applicable, associated child data is loaded.

Setup of DataTable Column:

If there is no corresponding child record,

    ->addColumn('codeId', function ($query) {
        return optional($query->modelcode)->codeId ?? 'N/A'; // Returns 'N/A'.
    })

When the associated child record is null, problems are avoided by using optional().
'N/A' will appear in the DataTable field if there are no child records linked to the parent.

1 like

marcoplus

1 year ago

Level 6

@jayandholariya thanks for your reply, if I view the parent table I see all the values and also the associated values in the child table, but a column where I have uploaded attachments I receive empty values the code I'm using to see the attachments is this I tried to insert it too but it doesn't work it remains empty

->addColumn('file', function ($query) {
                if ($query->file== null) {
                    return 'NA';
                }
                $array = explode(',', $query->file);

                $string = '';
                foreach ($array as $key => $value) {
                    $value = str_replace('//', '/', $value);
                    $url = ("https://s3.amazonaws.com/file/{$value}");
                    $key++;
                    $string .= "<a href='{$url}' target='_blank'>File- {$key} - {$query->createdAt}</a><br>";
                }
                return $string;
            })

this return all null

and if

->addColumn('file', function ($query) {
                if ($query->modelcode?->file== null) {  <---- ? and now work all
                    return 'NA';
                }
                $array = explode(',', $query->modelcode->file);

                $string = '';
                foreach ($array as $key => $value) {
                    $value = str_replace('//', '/', $value);
                    $url = ("https://s3.amazonaws.com/file/{$value}");
                    $key++;
                    $string .= "<a href='{$url}' target='_blank'>File- {$key} - {$query->modelcode->createdAt}</a><br>";
                }
                return $string;
            })

solved I was just missing a ? and now everything works, thanks for your support

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