adam@6: (** Common metaprogramming patterns for SQL syntax construction *)
adam@6: 
adam@6: val sqexps : env ::: {{Type}} -> fields ::: {Type} -> folder fields -> $(map sql_injectable fields)
adam@6:              -> $fields -> $(map (sql_exp env [] []) fields)
adam@6: (* Convert a record of Ur values into a record of SQL expressions *)
adam@6: 
adam@6: val selector : tn :: Name -> fs ::: {Type} -> ofs ::: {Type} -> [fs ~ ofs]
adam@6:                => folder fs -> $(map sql_injectable fs) -> $fs
adam@6:                -> sql_exp [tn = ofs ++ fs] [] [] bool
adam@6: (* Build a boolean SQL expression expressing equality of some fields of a table
adam@6:  * row with a record of Ur values *)
adam@13: 
adam@13: val joiner : tn1 :: Name -> tn2 :: Name -> fs ::: {Type} -> ofs1 ::: {Type} -> ofs2 ::: {Type}
adam@13:              -> [[tn1] ~ [tn2]] => [fs ~ ofs1] => [fs ~ ofs2]
adam@13:                => folder fs
adam@13:                -> sql_exp [tn1 = ofs1 ++ fs, tn2 = ofs2 ++ fs] [] [] bool
adam@13: (* Declare equality of same-named columns from two tables. *)
adam@15: 
adam@15: val insertIfMissing : keyCols ::: {Type} -> otherCols ::: {Type} -> otherKeys ::: {{Unit}}
adam@15:                       -> [keyCols ~ otherCols] => [[Pkey] ~ otherKeys]
adam@15:                       => sql_table (keyCols ++ otherCols) ([Pkey = map (fn _ => ()) keyCols] ++ otherKeys)
adam@15:                       -> $(keyCols ++ otherCols)
adam@15:                       -> folder keyCols -> $(map sql_injectable keyCols)
adam@15:                       -> folder otherCols -> $(map sql_injectable otherCols)
adam@15:                       -> transaction bool
adam@15: (* Insert a row into an SQL table if its key isn't already present, returning [False] iff the key was already present *)
adam@15: 
adam@15: val deleteByKey : keyCols ::: {Type} -> otherCols ::: {Type} -> otherKeys ::: {{Unit}}
adam@15:                   -> [keyCols ~ otherCols] => [[Pkey] ~ otherKeys]
adam@15:                   => sql_table (keyCols ++ otherCols) ([Pkey = map (fn _ => ()) keyCols] ++ otherKeys)
adam@15:                   -> $keyCols -> folder keyCols -> $(map sql_injectable keyCols)
adam@15:                   -> transaction {}
adam@15: (* Delete a row from a table by matching its primary key against a given record. *)