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module Simple_thread : PGOCaml_generic.THREAD with type 'a t = 'a
include PGOCaml_generic.PGOCAML_GENERIC with type 'a monad = 'a
For errors generated by the PostgreSQL database back-end. The * first argument is a printable error message. The second argument * is the complete set of error fields returned from the back-end. * See http://www.postgresql.org/docs/8.1/static/protocol-error-fields.html
val connect :
?host:string ->
?port:int ->
?user:string ->
?password:string ->
?database:string ->
?unix_domain_socket_dir:string ->
unit ->
'a t monad
Connect to the database. The normal $PGDATABASE
, etc. environment * variables are available.
Close the database handle. You must call this after you have * finished with the handle, or else you will get leaked file * descriptors.
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.
Start a transaction.
val transact :
'a t ->
?isolation:isolation ->
?access:access ->
?deferrable:bool ->
('a t -> 'b monad) ->
'b monad
transact db ?isolation ?access ?deferrable f
wraps your * function f
inside a transactional block. * First it calls begin_work
with isolation
, access
and deferrable
, * then calls f
and do rollback
if f
raises * an exception, commit
otherwise.
This is a shorthand for SELECT CURRVAL(serial)
. For a table * called table
with serial column id
you would typically * call this as serial dbh "table_id_seq"
after the previous INSERT * operation to get the serial number of the inserted row.
As serial
but assumes that the column is a SERIAL or * SERIAL4 type.
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.
Verbosity. 0 means don't print anything. 1 means print short * error messages as returned from the back-end. 2 means print all * messages as returned from the back-end. Messages are printed on stderr
. * Default verbosity level is 1.
val set_private_data : 'a t -> 'a -> unit
Attach some private data to the database handle. * * NB. The pa_pgsql camlp4 extension uses this for its own purposes, which * means that in most programs you will not be able to attach private data * to the database handle.
val private_data : 'a t -> 'a
Retrieve some private data previously attached to the database handle. * If no data has been attached, raises Not_found
. * * NB. The pa_pgsql camlp4 extension uses this for its own purposes, which * means that in most programs you will not be able to attach private data * to the database handle.
val uuid : 'a t -> string
Retrieve the unique identifier for this connection.
When using pa_pgsql, database handles have type * PGOCaml.pa_pg_data PGOCaml.t
type row = result list
None is NULL.
One row is a list of fields.
prepare conn ~query ?name ?types ()
prepares the statement query
* and optionally names it name
and sets the parameter types to types
. * If no name is given, then the "unnamed" statement is overwritten. If * no types are given, then the PostgreSQL engine infers types. * Synchronously checks for errors.
execute conn ?name ~params ()
executes the named or unnamed * statement name
, with the given parameters params
, * returning the result rows (if any). * * There are several steps involved at the protocol layer: * (1) a "portal" is created from the statement, binding the * parameters in the statement (Bind). * (2) the portal is executed (Execute). * (3) we synchronise the connection (Sync). * * The optional ?portal
parameter may be used to name the portal * created in step (1) above (otherwise the unnamed portal is used). * This is only important if you want to call describe_portal
* to find out the result types.
close_statement conn ?name ()
closes a prepared statement and frees * up any resources.
close_portal conn ?portal ()
closes a portal and frees up any resources.
inject conn ?name query
executes the statement query
* and optionally names it name
and gives the result.
alter conn ?name query
executes the statement query
* and optionally names it name
. Same as inject but ignoring the result.
type row_description = result_description list
type params_description = param_description list
val describe_statement :
'a t ->
?name:string ->
unit ->
(params_description * row_description option) monad
describe_statement conn ?name ()
describes the named or unnamed * statement's parameter types and result types.
val describe_portal :
'a t ->
?portal:string ->
unit ->
row_description option monad
describe_portal conn ?portal ()
describes the named or unnamed * portal's result types.
val name_of_type : ?modifier:int32 -> oid -> string
Returns the OCaml equivalent type name to the PostgreSQL type oid
. * For instance, name_of_type (Int32.of_int 23)
returns "int32"
because * the OID for PostgreSQL's internal int4
type is 23
. As another * example, name_of_type (Int32.of_int 25)
returns "string"
.
type timestamptz = CalendarLib.Calendar.t * CalendarLib.Time_Zone.t
The following conversion functions are used by pa_pgsql to convert * values in and out of the database.
val string_of_oid : oid -> string
val string_of_int16 : int16 -> string
val string_of_point : point -> string
val string_of_hstore : hstore -> string
val string_of_numeric : numeric -> string
val string_of_uuid : uuid -> string
val string_of_jsonb : jsonb -> string
val string_of_inet : inet -> string
val string_of_timestamp : CalendarLib.Calendar.t -> string
val string_of_timestamptz : timestamptz -> string
val string_of_date : CalendarLib.Date.t -> string
val string_of_time : CalendarLib.Time.t -> string
val string_of_interval : CalendarLib.Calendar.Period.t -> string
val string_of_bytea : bytea -> string
val string_of_bool_array : bool_array -> string
val string_of_int32_array : int32_array -> string
val string_of_int64_array : int64_array -> string
val string_of_string_array : string_array -> string
val string_of_float_array : float_array -> string
val oid_of_string : string -> oid
val int16_of_string : string -> int16
val point_of_string : string -> point
val hstore_of_string : string -> hstore
val numeric_of_string : string -> numeric
val uuid_of_string : string -> uuid
val jsonb_of_string : string -> jsonb
val inet_of_string : string -> inet
val timestamp_of_string : string -> CalendarLib.Calendar.t
val timestamptz_of_string : string -> timestamptz
val date_of_string : string -> CalendarLib.Date.t
val time_of_string : string -> CalendarLib.Time.t
val interval_of_string : string -> CalendarLib.Calendar.Period.t
val bytea_of_string : string -> bytea
val bool_array_of_string : string -> bool_array
val int32_array_of_string : string -> int32_array
val int64_array_of_string : string -> int64_array
val string_array_of_string : string -> string_array
val float_array_of_string : string -> float_array
val return : 'a -> 'a monad