42 lines
916 B
Haskell
42 lines
916 B
Haskell
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module ChuSQL.Syntax.Ast where
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-- 查询语句
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data Query
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= Select
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{ selectCols :: [String]
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, selectTable :: String
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, selectWhere :: Maybe Expr
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, selectOrderBy :: [(String, SortDir)]
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, selectLimit :: Maybe Int
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}
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| Insert String [String] [Expr]
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| Delete String (Maybe Expr)
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| Update String [(String, Expr)] (Maybe Expr)
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deriving (Show, Eq)
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-- 条件表达式
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data Expr
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= Col String
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| LitInt Int
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| LitStr String
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| Gt Expr Expr
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| Lt Expr Expr
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| Eq Expr Expr
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| And Expr Expr
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| Or Expr Expr
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deriving (Show, Eq)
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data SortDir
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= Asc
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| Desc
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deriving (Show, Eq)
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makeSelect :: [String] -> String -> Maybe Expr -> Query
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makeSelect cols tbl w =
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Select
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{ selectCols = cols
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, selectTable = tbl
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, selectWhere = w
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, selectOrderBy = []
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, selectLimit = Nothing
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}
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