Laravel Check If Related Model Exists

Question

I have an Eloquent model which has a related model   public function option         return  this- gt hasOne  RepairOption    repair item id       public function setOptionArrayAttribute  values         this- gt option- gt update  values       When I create the model  it does not necessarily have a related model  When I update it  I might add an option  or not   So I need to check if the related model exists  to either update it  or create it  respectively    model   RepairItem  find  id   if  Input  has  option          if   lt related model exists gt              option   new RepairOption Input  get  option              option- gt repairItem  - gt associate  model            option- gt save             model- gt fill Input  except  option          else           model- gt update Input  all                Where  lt related model exists gt  is the code I am looking for

User · Accepted Answer

In php 7 2  you can t use count on the relation object  so there s no one-fits-all method for all relations  Use query method instead as  tremby provided below    model- gt relation  - gt exists       generic solution working on all the relation types  pre php 7 2    if  count  model- gt relation          exists     This will work for every relation since dynamic properties return Model or Collection  Both implement ArrayAccess   So it goes like this   single relations  hasOne   belongsTo   morphTo   morphOne     no related model  model- gt relation     null count  model- gt relation      0 evaluates to false     there is one  model- gt relation     Eloquent Model count  model- gt relation      1 evaluates to true   to-many relations  hasMany   belongsToMany   morphMany   morphToMany   morphedByMany     no related collection  model- gt relation     Collection with 0 items evaluates to true count  model- gt relation      0 evaluates to false     there are related models  model- gt relation     Collection with 1 or more items  evaluates to true as well count  model- gt relation      int  gt  0 that evaluates to true

User · Answer

I had to completely refactor my code when I updated my PHP version to 7 2  because of bad usage of the count  x  function  This is a real pain and its also extremely scary as there are hundreds usages  in different scenarios and there is no one rules fits all    Rules I followed to refactor everything  examples    x   Auth  user  - posts- find 6    check if user has a post id 6 using - find      FAILS  if count  x     return  Found       GOOD  if  x    return  Found        x   Auth  user  - profile- departments   check if profile has some departments  there can have many departments    FAILS  if count  x     return  Found      GOOD  if  x- gt count      return  Found        x   Auth  user  - profile- get     check if user has a profile after using a - get      FAILS  if count  x     return  Found      GOOD  if  x- gt count      return  Found       Hopes this can help  even 5 years after the question has been asked  this stackoverflow post has helped me a lot

User · Answer

I prefer to use exists method   RepairItem  find  id - gt option  - gt exists    to check if related model exists or not  It s working fine on Laravel 5 2

User · Answer

As Hemerson Varela already said in Php 7 1 count null  will throw an error and hasOne returns null if no row exists  Since you have a hasOnerelation I would use the empty method to check    model   RepairItem  find  id   if   empty  temp    request- gt input  option           option    model- gt option      if empty  option           option    model- gt option  - gt create              option- gt someAttribute   temp      option- gt save         But this is superfluous  There is no need to check if the relation exists  to determine if you should do an update or  a create call  Simply use the updateOrCreate method  This is equivalent to the above    model   RepairItem  find  id   if   empty  temp    request- gt input  option             model- gt option            - gt updateOrCreate   repair item id    gt   model- gt id                               option    gt   temp

User · Answer

You can use the relationLoaded method on the model object  This saved my bacon so hopefully it helps someone else  I was given this suggestion when I asked the same question on Laracasts

User · Answer

Not sure if this has changed in Laravel 5  but the accepted answer using count  data- gt  relation  didn t work for me  as the very act of accessing the relation property caused it to be loaded   In the end  a straightforward isset  data- gt  relation  did the trick for me

User · Answer

A Relation object passes unknown method calls through to an Eloquent query Builder  which is set up to only select the related objects  That Builder in turn passes unknown method calls through to its underlying query Builder   This means you can use the exists   or count   methods directly from a relation object    model- gt relation  - gt exists       bool  true if there is at least one row  model- gt relation  - gt count       int  number of related rows   Note the parentheses after relation  - gt relation   is a function call  getting the relation object   as opposed to - gt relation which a magic property getter set up for you by Laravel  getting the related object objects    Using the count method on the relation object  that is  using the parentheses  will be much faster than doing  model- gt relation- gt count   or count  model- gt relation   unless the relation has already been eager-loaded  since it runs a count query rather than pulling all of the data for any related objects from the database  just to count them  Likewise  using exists doesn t need to pull model data either   Both exists   and count   work on all relation types I ve tried  so at least belongsTo  hasOne  hasMany  and belongsToMany

User · Answer

After Php 7 1  The accepted answer won t work for all types of relationships   Because depending of type the relationship  Eloquent will return a Collection  a Model or Null  And in Php 7 1 count null  will throw an error     So  to check if the relation exist you can use   For relationships single  For example hasOne and belongsTo  if  is null  model- gt relation                 For relationships multiple  For Example  hasMany and belongsToMany  if   model- gt relation- gt isNotEmpty

[php] Laravel Check If Related Model Exists

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