83 lines
2.7 KiB
Haskell
83 lines
2.7 KiB
Haskell
module Main where
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import ChuSQL.Algebra.Op (renderPlan)
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import ChuSQL.Algebra.Optimize (optimize)
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import ChuSQL.Algebra.Planner (translate)
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import ChuSQL.Engine
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import ChuSQL.Model
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import ChuSQL.Syntax.AST
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import ChuSQL.Syntax.Parser
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-- 命令行演示：跑几条语句，打印结果与优化前后的计划。
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users :: Table
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users =
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Table
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{ tableName = "users"
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, tableCols = [("id", TInt), ("name", TStr), ("age", TInt)]
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, tableRows =
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[ [("id", VInt 1), ("name", VStr "Alice"), ("age", VInt 25)]
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, [("id", VInt 2), ("name", VStr "Bob"), ("age", VInt 17)]
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, [("id", VInt 3), ("name", VStr "Carol"), ("age", VInt 30)]
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]
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}
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orders :: Table
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orders =
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Table
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{ tableName = "orders"
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, tableCols = [("id", TInt), ("user_id", TInt), ("product", TStr)]
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, tableRows =
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[ [("id", VInt 1), ("user_id", VInt 1), ("product", VStr "Book")]
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, [("id", VInt 2), ("user_id", VInt 2), ("product", VStr "Pen")]
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, [("id", VInt 3), ("user_id", VInt 1), ("product", VStr "Cup")]
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]
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}
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db :: Database
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db = [("users", users), ("orders", orders)]
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-- | 演示入口
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main :: IO ()
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main = do
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putStrLn "==================== Engine ====================="
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let q1 = makeSelect ["name"] "users" (Just (Gt (Col "age") (LitInt 18)))
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print (rowsOf (runStatement db q1))
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let q2 = makeSelect ["*"] "users" Nothing
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print (rowsOf (runStatement db q2))
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let q3 = makeSelect ["name"] "nonexistent" Nothing
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print (rowsOf (runStatement db q3))
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let q4 =
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makeSelect
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["name"]
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"users"
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( Just
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( Or
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(Lt (Col "age") (LitInt 18))
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(Gt (Col "age") (LitInt 30))
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)
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)
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print (rowsOf (runStatement db q4))
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let parsed = parseStatement "SELECT name FROM users WHERE age > 18 AND name = 'Alice'"
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print (rowsOf (parsed >>= runStatement db))
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putStrLn "\n==================== Optimizer ====================="
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let planSql =
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"SELECT u.name, o.product FROM users u \
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\JOIN orders o ON u.id = o.user_id WHERE u.age > 18"
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case parseStatement planSql of
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Left err -> putStrLn err
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Right query -> case translate query of
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Left err -> putStrLn err
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Right plan -> do
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putStrLn "--- plan before optimization ---"
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putStrLn (renderPlan plan)
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putStrLn "--- plan after optimization ---"
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putStrLn (renderPlan (optimize db plan))
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putStrLn "--- rows ---"
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print (rowsOf (runStatement db query))
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