152 lines
3.7 KiB
OCaml
152 lines
3.7 KiB
OCaml
type query =
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(*| Select of column list * table list option * filter option*)
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| Select of column list * table_expression
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| CreateSchema of string
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| CreateTable of table
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| DropSchema of string
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| DropTable of table
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and column =
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| Asterisk
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(* | Column of string *)
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| Column of expression * as_clause option
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and as_clause =
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| As of string
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and table_expression =
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| TableExpression of table list option * filter option * group option
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and table =
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| Table of string
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| Join of table * join_type * table * condition option
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and join_type =
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| Inner
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| Left
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| Right
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| Full
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| Cross
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| Union
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| Natural
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and condition =
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| Condition of predicand * predicate
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| And of condition * condition
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| Or of condition * condition
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| Not of condition
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and predicand = expression
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and predicate =
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| Comparison of operator * predicand
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| Between of predicand * predicand
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| NotBetween of predicand * predicand
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| In of predicand list
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| NotIn of predicand list
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| Like of predicand
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| NotLike of predicand
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and operator =
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| Equals
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| NotEquals
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| LessThan
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| GreaterThan
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| LessEquals
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| GreaterEquals
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and filter = condition
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and group =
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| Group of quantifier option * expression list option
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and aggregate =
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| Aggregate of func * filter option
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and func =
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| Function of function_type * quantifier option * expression
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and function_type =
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| Avg
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| Max
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| Min
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| Sum
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| Count
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and quantifier =
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| All
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| Distinct
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and expression =
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| Ref of string
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| StringLiteral of string
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| DateLiteral of string
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| TimeLiteral of string
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let rec pp_query fmt ast =
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match ast with
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| Select(cols, table_exp) -> Format.fprintf fmt "%s" (String.cat "SELECT " (pp_columns cols) ^ pp_table_expression table_exp)
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| _ -> failwith "not yet supported"
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and pp_columns cols =
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match cols with
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| [] -> ""
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| [col] -> pp_column col
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| col::l -> pp_column col ^ ", " ^ pp_columns l
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and pp_column col =
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match col with
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| Column(exp,_) -> pp_expression exp
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| Asterisk -> "*"
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and pp_expression exp =
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match exp with
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| Ref(name) -> name
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| StringLiteral(name) -> "'"^name^"'"
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| DateLiteral(name) -> "'"^name^"'"
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| TimeLiteral(name) -> "'"^name^"'"
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and pp_table_expression table_exp =
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match table_exp with
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| TableExpression(tables, filter, _) -> pp_tables tables ^ pp_filter filter
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and pp_tables tables =
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let rec aux t =
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match t with
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| [] -> ""
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| table::[] -> pp_table table
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| table::l -> pp_table table ^ ", " ^ aux l
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in
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match tables with
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| None -> ""
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| Some(t) -> " FROM " ^ aux t
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and pp_table table =
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match table with
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| Table(table) -> table
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| Join(t1, j, t2, _) -> pp_table t1 ^ pp_join_type j ^ pp_table t2
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and pp_join_type j =
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match j with
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| Inner -> "inner"
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| Left -> "left"
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| Right -> "right"
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| Full -> "full"
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| Cross -> "cross"
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| Union -> "union"
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| Natural -> "natural"
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and pp_filter filter =
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let rec aux f =
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match f with
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| Condition(exp, pred) -> pp_expression exp ^ " " ^ pp_predicate pred
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| And(c1, c2) -> aux c1 ^ " AND " ^ aux c2
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| Or(c1, c2) -> aux c1 ^ " OR " ^ aux c2
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| Not(c) -> "NOT" ^ aux c
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in
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match filter with
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| None -> ""
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| Some(f) -> " WHERE " ^ aux f
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and pp_predicate pred =
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match pred with
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| Comparison(op, exp) -> pp_operator op ^ pp_expression exp
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| Between(exp1, exp2) -> "BETWEEN " ^ pp_expression exp1 ^ " AND " ^pp_expression exp2
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| NotBetween(exp1, exp2) -> "NOT BETWEEN " ^ pp_expression exp1 ^ " AND " ^pp_expression exp2
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| Like(exp) -> "LIKE " ^ pp_expression exp
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| NotLike(exp) -> " NOT LIKE " ^ pp_expression exp
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| _ -> failwith "Predicate not supported"
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and pp_operator op =
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match op with
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| Equals -> "="
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| NotEquals -> "!="
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| LessThan -> "<"
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| GreaterThan -> ">"
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| LessEquals -> "<="
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| GreaterEquals -> ">="
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