Module `Postgresql`Source

Client-interface to the PostgreSQL database.

Please learn about more details in the database documentation!

Types

Sourcetype oid = int

Object ID (= Postgresql type of an object)

Sourcetype large_object

Handle for large objects

Sourcemodule FFormat : sig ... end

Type of field formats

Sourcetype ftype =

| BOOL
| BYTEA
| CHAR
| NAME
| INT8
| INT2
| INT2VECTOR
| INT4
| REGPROC
| TEXT
| OID
| TID
| XID
| CID
| OIDVECTOR
| JSON
| POINT
| LSEG
| PATH
| BOX
| POLYGON
| LINE
| FLOAT4
| FLOAT8
| ABSTIME
| RELTIME
| TINTERVAL
| UNKNOWN
| CIRCLE
| CASH
| MACADDR
| INET
| CIDR
| ACLITEM
| BPCHAR
| VARCHAR
| DATE
| TIME
| TIMESTAMP
| TIMESTAMPTZ
| INTERVAL
| TIMETZ
| BIT
| VARBIT
| NUMERIC
| REFCURSOR
| REGPROCEDURE
| REGOPER
| REGOPERATOR
| REGCLASS
| REGTYPE
| RECORD
| CSTRING
| ANY
| ANYARRAY
| VOID
| TRIGGER
| LANGUAGE_HANDLER
| INTERNAL
| OPAQUE
| ANYELEMENT
| JSONB

Type of fields

Sourcemodule Error_field : sig ... end

Sourcemodule Error_code : sig ... end

Sourcetype result_status =

| Empty_query
(*
String sent to the backend was empty
*)
| Command_ok
(*
Successful completion of a command returning no data
*)
| Tuples_ok
(*
The query successfully executed
*)
| Copy_out
(*
Copy Out (from server) data transfer started
*)
| Copy_in
(*
Copy In (to server) data transfer started
*)
| Bad_response
(*
The server's response was not understood
*)
| Nonfatal_error
| Fatal_error
| Copy_both
| Single_tuple
(*
One tuple of a result set (set_single_row_mode)
*)

Status of command/query results

Sourcetype put_copy_result =

| Put_copy_queued
(*
Data queued
*)
| Put_copy_not_queued
(*
Data not queued due to full bufffers (async only)
*)
| Put_copy_error
(*
Copying failed, see #error_message for details
*)

Result of put_copy_data and put_copy_end

Sourcetype get_copy_result =

| Get_copy_data of string
(*
Data corresponding to one row is returned
*)
| Get_copy_wait
(*
The next row is still being received (async only); wait for read-only, call consume_input, and try again
*)
| Get_copy_end
(*
All data has been successfully retrieved
*)
| Get_copy_error
(*
Copying failed, see #error_message for details
*)

Result of get_copy_data

Sourcetype getline_result =

| EOF
(*
End of input reached
*)
| LineRead
(*
Entire line has been read
*)
| BufFull
(*
Buffer full but terminating newline not encountered
*)

Result of getline

Sourcetype getline_async_result =

| EndOfData
(*
End-of-copy-data marker recognized
*)
| NoData
(*
No data available
*)
| DataRead of int
(*
DataRead n indicates n bytes of read data
*)
| PartDataRead of int
(*
Like DataRead, but data only partially read
*)

Result of getline_async

Sourcetype seek_cmd =

| SEEK_SET
(*
Seek from start of large object
*)
| SEEK_CUR
(*
Seek from current read/write position of large object
*)
| SEEK_END
(*
Seek from end of large object
*)

Seek command ("whence")

Exceptions and error handling

Sourcetype error =

| Field_out_of_range of int * int
| Tuple_out_of_range of int * int
| Binary
| Connection_failure of string
| Unexpected_status of result_status * string * result_status list
| Cancel_failure of string

Kinds of exceptions:

Field_out_of_range (i, n) - access to field i not within range n Tuple_out_of_range (i, n) - access to tuple i not within range n Binary - result consists of binary tuple data Connection_failure msg - connection failed due to reason msg Unexpected_status (stat, msg, expected) - result status stat was not in expected due to error msg

Sourceexception Error of error

Error error indicates an error

Sourceval string_of_error : error -> string

string_of_error error convert error to a human-readable message

Sourceexception Oid of oid

Oid oid conversion from an oid to an ftype encountered an unknown oid

Utility functions

Sourceval unescape_bytea : string -> string

unescape_bytea str unescapes binary string str. This function supports the new hex format for encoding bytea strings (introduced in Postgresql 9.0) even if the local libpq library is from an older version.

Sourceval ftype_of_oid : oid -> ftype

ftype_of_oid oid converts oid to an ftype.

Sourceval oid_of_ftype : ftype -> oid

oid_of_ftype ftype converts ftype to an oid.

Sourceval string_of_ftype : ftype -> string

string_of_ftype ftype converts ftype to a string.

Sourceval ftype_of_string : string -> ftype

string_of_ftype ftype converts string to a ftype.

Handling results of commands and queries

Sourceval result_status : result_status -> string

result_status stat convert status stat to a human-readable message

Sourceval invalid_oid : oid

invalid_oid invalid Oid.

Query parameters

Sourceval null : string

null can be used as an element of the optional argument parameters passed to the exec or send_query method to indicate a NULL value.

Sourceclass type result = object ... end

Class type of query results.

Handling database connections

Sourcetype connection_status =

| Ok
| Bad
| Connection_started
| Connection_made
| Connection_awaiting_response
| Connection_auth_ok
| Connection_setenv
| Connection_ssl_startup

Status of a connection

Sourcetype polling_status =

| Polling_failed
| Polling_reading
| Polling_writing
| Polling_ok

Polling status used while establishing a connection asynchronously.

Sourcetype flush_status =

| Successful
| Data_left_to_send

Result of a call to flush on nonblocking connections.

Sourcetype conninfo_option = {

cio_keyword : string;
(*
Keyword of option
*)
cio_envvar : string option;
(*
Fallback environment variable name
*)
cio_compiled : string option;
(*
Fallback compiled in default value
*)
cio_val : string option;
(*
Current value of option, or NULL
*)
cio_label : string;
(*
Label for field in connect dialog
*)
cio_dispchar : string;
(*
Character to display for this field in dialog
*)
cio_dispsize : int;
(*
Field size in characters for dialog
*)

}

Record of connection options

Sourcemodule Notification : sig ... end

Type of asynchronous notifications

Sourceval conndefaults : unit -> conninfo_option array

conndefaults ()

returns
array of all records of type conninfo_option

Source

class connection : ?host:string -> ?hostaddr:string -> ?port:string -> ?dbname:string -> ?user:
  string -> ?password:string -> ?options:string -> ?tty:string -> ?requiressl:
  string -> ?conninfo:string -> ?startonly:bool -> unit -> object ... end

Class of connections.

package postgresql

Module PostgresqlSource