module Io : sig ... end
val connect : ?ssl:[ `Auto | `No | `Always of Io.ssl_config ] -> ?host:string -> ?port:int -> ?user:string -> ?password:string -> ?database:string -> ?unix_domain_socket_dir:string -> ?verbose:int -> ?max_message_length:int -> unit -> t Io.t
Connect to the database. The normal
$PGDATABASE, etc. environment variables are available.
max_message_length is the maximum message length accepted from the back-end. The default is
Sys.max_string_length, which means that we will try to read as much data from the back-end as we can, and this may cause us to run out of memory (particularly on 64 bit machines), causing a possible denial of service. You may want to set this to a smaller size to avoid this happening.
Close the database handle. You must call this after you have finished with the handle, or else you will get leaked file descriptors.
val with_conn : ?ssl:[ `Auto | `No | `Always of Io.ssl_config ] -> ?host:string -> ?port:int -> ?user:string -> ?password:string -> ?database:string -> ?unix_domain_socket_dir:string -> ?verbose:int -> ?max_message_length:int -> (t -> 'a Io.t) -> 'a Io.t
connect, passes the DB handle to the callback, then calls
close. This is the preferred way to use this library since it cleans up after itself.
Ping the database. If the database is not available, some sort of exception will be thrown.
This function is a wrapper of
ping that returns a boolean instead of raising an exception.
val begin_work : ?isolation:Isolation.t -> ?access:Access.t -> ?deferrable:bool -> t -> t Io.t
Start a transaction.
Commit a transaction. Throws an exception if no transaction is open. Use
with_transaction when possible.
Rollback a transaction. Throws an exception if no transaction is open. Use
with_transaction when possible.
val with_transaction : ?isolation:Isolation.t -> ?access:Access.t -> ?deferrable:bool -> t -> (t -> 'b Io.t) -> 'b Io.t
with_transaction db ?isolation ?access ?deferrable f wraps your function
f inside a transactional block. See
begin_work for a description of
f throws an exception, the transaction will be rolled back. Otherwise the transaction will be commited. It is an error to call
rollback manually inside of this function.
module Prepared : sig ... end
val execute : ?params:Pgx__.Pgx_value.v option list -> t -> string -> Pgx__.Pgx_value.v option list list Io.t
execute conn ?params query prepares and executes the statement
query and returns the result.
execute_unit conn ?params query same as execute, but intended for database calls that have side-affects rather than returning results
val execute_many : t -> query:string -> params:Pgx__.Pgx_value.v option list list -> Pgx__.Pgx_value.v option list list list Io.t
Prepares a query as in
execute and then executes it once per set of parameters in
params. This is more efficient than calling
execute in a loop because the query is only prepared once.
simple_query conn query executes the command(s) in the given
query and returns a list of query results (i.e. if you run two queries, you will get a list with two elements: the results of the first query followed by the results of the second query.