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Module Postgresql


module Postgresql: sig .. end
Client-interface to the PostgreSQL database.

Please learn about more details in the database documentation!

Types

type oid = int
Object ID (= Postgresql type of an object)
type large_object
Handle for large objects
module FFormat: sig .. end
Type of field formats

type ftype =
| BOOL
| BYTEA
| CHAR
| NAME
| INT8
| INT2
| INT2VECTOR
| INT4
| REGPROC
| TEXT
| OID
| TID
| XID
| CID
| OIDVECTOR
| 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
Type of fields

type 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
Status of command/query results

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

type 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

type 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


type 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

exception Error of error
Error error indicates an error
val string_of_error : error -> string
string_of_error error convert error to a human-readable message
exception Oid of oid
Oid oid conversion from an oid to an ftype encountered an unknown oid

Utility functions

val unescape_bytea : string -> string
unescape_bytea str unescapes binary string str.
val ftype_of_oid : oid -> ftype
ftype_of_oid oid converts oid to an ftype.
val oid_of_ftype : ftype -> oid
oid_of_ftype ftype converts ftype to an oid.
val string_of_ftype : ftype -> string
string_of_ftype ftype converts ftype to a string.
val ftype_of_string : string -> ftype
string_of_ftype ftype converts ftype to a string.

Handling results of commands and queries

val result_status : result_status -> string
result_status stat convert status stat to a human-readable message
val invalid_oid : oid
invalid_oid invalid Oid.

Query parameters

val 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.
class type result = object .. end
Class type of query results.

Handling database connections


type connection_status =
| Ok
| Bad
Status of a connection

type conninfo_option = {
   cio_keyword : string; (*Keyword of option*)
   cio_envvar : string; (*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
val conndefaults : unit -> conninfo_option array
conndefaults ()
Returns array of all records of type conninfo_option
class connection : ?host:string -> ?hostaddr:string -> ?port:string -> ?dbname:string -> ?user:string -> ?password:string -> ?options:string -> ?tty:string -> ?requiressl:string -> ?conninfo:string -> unit -> object .. end
Class of connections.