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default values for PersistList on SQLite - Yesod

Comparing Haskell's Snap and Yesod web frameworksExceptions in YesodMongoDB Example for Yesod / Persistentyesod persistent: get Entity value within hamletYesod migrating custom data typesPersistMap in Yesod?Yesod Persistent: SQLite table with id row onlyError with Persistent syntax using MySQL and YesodYesod CSS luciusYesod: Passing the current user to a form

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;

0

I would like to add a PersistList value into a user entity with a default value. My model file looks like this. And Models.hs file:

User
 ident Text
 password Text Maybe
 UniqueUser ident
 perms [Privileges] default=[PrvDemoOne]
 deriving Typeable

---

data Privileges =
 PrvDemoOne -- ^ what can be demo one...
 | PrvDemoTwo -- ^ what can be demo two...
 deriving (Show,Read,Eq)

derivePersistField "Privileges"

the code compiles but when a new user is added into the table save an empty array instead of an array with the default value.

1|google-uid:223344555661778819911||[]

The question is how I could save the column with the default value?

haskell yesod persistent

share|improve this question

edited May 5 at 9:49

recnac

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asked Mar 27 at 15:25

oriajoriaj

41388 silver badges2626 bronze badges

add a comment | 

0

I would like to add a PersistList value into a user entity with a default value. My model file looks like this. And Models.hs file:

User
 ident Text
 password Text Maybe
 UniqueUser ident
 perms [Privileges] default=[PrvDemoOne]
 deriving Typeable

---

data Privileges =
 PrvDemoOne -- ^ what can be demo one...
 | PrvDemoTwo -- ^ what can be demo two...
 deriving (Show,Read,Eq)

derivePersistField "Privileges"

the code compiles but when a new user is added into the table save an empty array instead of an array with the default value.

1|google-uid:223344555661778819911||[]

The question is how I could save the column with the default value?

haskell yesod persistent

share|improve this question

edited May 5 at 9:49

recnac

3,19766 gold badges99 silver badges3838 bronze badges

asked Mar 27 at 15:25

oriajoriaj

41388 silver badges2626 bronze badges

add a comment | 

I would like to add a PersistList value into a user entity with a default value. My model file looks like this. And Models.hs file:

User
 ident Text
 password Text Maybe
 UniqueUser ident
 perms [Privileges] default=[PrvDemoOne]
 deriving Typeable

---

data Privileges =
 PrvDemoOne -- ^ what can be demo one...
 | PrvDemoTwo -- ^ what can be demo two...
 deriving (Show,Read,Eq)

derivePersistField "Privileges"

the code compiles but when a new user is added into the table save an empty array instead of an array with the default value.

1|google-uid:223344555661778819911||[]

The question is how I could save the column with the default value?

haskell yesod persistent

share|improve this question

edited May 5 at 9:49

recnac

3,19766 gold badges99 silver badges3838 bronze badges

asked Mar 27 at 15:25

oriajoriaj

41388 silver badges2626 bronze badges

User
 ident Text
 password Text Maybe
 UniqueUser ident
 perms [Privileges] default=[PrvDemoOne]
 deriving Typeable

data Privileges =
 PrvDemoOne -- ^ what can be demo one...
 | PrvDemoTwo -- ^ what can be demo two...
 deriving (Show,Read,Eq)

derivePersistField "Privileges"

share|improve this question

edited May 5 at 9:49

recnac

3,19766 gold badges99 silver badges3838 bronze badges

asked Mar 27 at 15:25

oriajoriaj

41388 silver badges2626 bronze badges

share|improve this question

edited May 5 at 9:49

recnac

3,19766 gold badges99 silver badges3838 bronze badges

asked Mar 27 at 15:25

oriajoriaj

41388 silver badges2626 bronze badges

edited May 5 at 9:49

recnac

3,19766 gold badges99 silver badges3838 bronze badges

edited May 5 at 9:49

recnac

3,19766 gold badges99 silver badges3838 bronze badges

asked Mar 27 at 15:25

oriajoriaj

41388 silver badges2626 bronze badges

asked Mar 27 at 15:25

oriajoriaj

41388 silver badges2626 bronze badges

1 Answer
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0

Have you read this? The value of the default field doesn't really have anything to do with the Haskell side per-se, it's being passed to set the "default value" description your DBMS. In this case [PrvDemoOne] is being passed directly to SQLite, which will interpret it as gibberish (because it's not a valid SQL expression) so this is either ignored or (what seems to be the case here) treated as if you hadn't set a default at all.

If you want a "Haskell side" default value you should just create a function for that, i.e. something like

defaultUser :: Text -> Maybe Text -> User
defaultUser i maybePw = User ident = i, password = maybePw, perms = [PrvDemoOne] 

If you want a SQL side default you need to write the corresponding SQL expression for the value you're trying to represent.

On a non-Haskell related note: the 'normal' way to represent lists (or sets in this case, rather!) in SQL is via relations, so you'd normally have a many-to-many relationship mapping users to their privileges instead of a list field.

share|improve this answer

answered Mar 27 at 16:07

CubicCubic

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add a comment | 

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0

Have you read this? The value of the default field doesn't really have anything to do with the Haskell side per-se, it's being passed to set the "default value" description your DBMS. In this case [PrvDemoOne] is being passed directly to SQLite, which will interpret it as gibberish (because it's not a valid SQL expression) so this is either ignored or (what seems to be the case here) treated as if you hadn't set a default at all.

If you want a "Haskell side" default value you should just create a function for that, i.e. something like

defaultUser :: Text -> Maybe Text -> User
defaultUser i maybePw = User ident = i, password = maybePw, perms = [PrvDemoOne] 

If you want a SQL side default you need to write the corresponding SQL expression for the value you're trying to represent.

On a non-Haskell related note: the 'normal' way to represent lists (or sets in this case, rather!) in SQL is via relations, so you'd normally have a many-to-many relationship mapping users to their privileges instead of a list field.

share|improve this answer

answered Mar 27 at 16:07

CubicCubic

11.7k33 gold badges3434 silver badges7676 bronze badges

add a comment | 

0

Have you read this? The value of the default field doesn't really have anything to do with the Haskell side per-se, it's being passed to set the "default value" description your DBMS. In this case [PrvDemoOne] is being passed directly to SQLite, which will interpret it as gibberish (because it's not a valid SQL expression) so this is either ignored or (what seems to be the case here) treated as if you hadn't set a default at all.

If you want a "Haskell side" default value you should just create a function for that, i.e. something like

defaultUser :: Text -> Maybe Text -> User
defaultUser i maybePw = User ident = i, password = maybePw, perms = [PrvDemoOne] 

If you want a SQL side default you need to write the corresponding SQL expression for the value you're trying to represent.

On a non-Haskell related note: the 'normal' way to represent lists (or sets in this case, rather!) in SQL is via relations, so you'd normally have a many-to-many relationship mapping users to their privileges instead of a list field.

share|improve this answer

answered Mar 27 at 16:07

CubicCubic

11.7k33 gold badges3434 silver badges7676 bronze badges

add a comment | 

Have you read this? The value of the default field doesn't really have anything to do with the Haskell side per-se, it's being passed to set the "default value" description your DBMS. In this case [PrvDemoOne] is being passed directly to SQLite, which will interpret it as gibberish (because it's not a valid SQL expression) so this is either ignored or (what seems to be the case here) treated as if you hadn't set a default at all.

If you want a "Haskell side" default value you should just create a function for that, i.e. something like

defaultUser :: Text -> Maybe Text -> User
defaultUser i maybePw = User ident = i, password = maybePw, perms = [PrvDemoOne] 

If you want a SQL side default you need to write the corresponding SQL expression for the value you're trying to represent.

On a non-Haskell related note: the 'normal' way to represent lists (or sets in this case, rather!) in SQL is via relations, so you'd normally have a many-to-many relationship mapping users to their privileges instead of a list field.

share|improve this answer

answered Mar 27 at 16:07

CubicCubic

11.7k33 gold badges3434 silver badges7676 bronze badges

defaultUser :: Text -> Maybe Text -> User
defaultUser i maybePw = User ident = i, password = maybePw, perms = [PrvDemoOne] 

share|improve this answer

answered Mar 27 at 16:07

CubicCubic

11.7k33 gold badges3434 silver badges7676 bronze badges

answered Mar 27 at 16:07

CubicCubic

11.7k33 gold badges3434 silver badges7676 bronze badges

answered Mar 27 at 16:07

CubicCubic

11.7k33 gold badges3434 silver badges7676 bronze badges