package caqti

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Query specification.

type t =
  1. | L of string
    (*

    Literal code. May contain incomplete fragments.

    *)
  2. | Q of string
    (*

    Q s corresponds to a TEXT literal; passed as part of the query string if a suitable quoting function is available in the client library, otherwise passed as an additional parameter.

    *)
  3. | P of int
    (*

    P i refers to parameter number i, counting from 0.

    *)
  4. | S of t list
    (*

    S frags is the concatenation of frags.

    *)

A representation of a query string to send to a database, abstracting over parameter references and providing nested concatenation to simplify generation. For databases which only support linear parameters (typically denoted "?"), the driver will reshuffle, elide, and duplicate parameters as needed.

val normal : t -> t

normal q rewrites q to a normal form containing at most one top-level S constructor, containing no empty literals, and no consecutive literals. This function can be used to post-process queries before using equal and hash.

val equal : t -> t -> bool

Equality predicate for query.

val hash : t -> int

A hash function compatible with equal. This is currently Hashtbl.hash.

val pp : Stdlib.Format.formatter -> t -> unit

pp ppf q prints a human-readable representation of q on ppf. The printed string is not suitable for sending to an SQL database; doing so may lead to an SQL injection vulnerability.

val show : t -> string

show q is the same human-readable representation of q as printed by pp. The returned string is not suitable for sending to an SQL database; doing so may lead to an SQL injection vulnerability.

val concat : string -> t list -> t

concat sep frags is frags interfixed with sep if frags is non-empty and the empty string of frags is empty.