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Marzin edited this page Jun 24, 2021 · 12 revisions

PostgreSQLClient DOCUMENTATION (NOT FINALIZED):

PROPERTIES:

Type Properties Default value
float PROTOCOL_VERSION const 3.0
dictionary parameter_status reader alone {}

METHODS:

Type Method
Error connect_to_host(url: String, ssl: bool = false, connect_timeout: int = 30)
Array execute(sql: String)
void rollback(process_id: int, process_key: int)
void close(clean_closure: bool = true)
void set_ssl_connection()

SIGNALS:

Signal
connection_closed(was_clean_close: bool)
connection_error()
connection_established()

ENUMARATIONS:

enum DataTypePostgreSQL

  • BOOLEAN = 16 --- Postgresql data type of type boolean.
  • SMALLINT = 21, --- Postgresql data type of type smallint.
  • INTEGER = 23, --- Postgresql data type of type integer.
  • BIGINT = 20, --- Postgresql data type of type bigint.
  • REAL = 700, --- Postgresql data type of type real.
  • DOUBLE_PRECISION = 701, --- Postgresql data type of type double precision.
  • TEXT = 25, --- Postgresql data type of type text.
  • JSON = 114, --- Postgresql data type of type json.
  • JSONB = 3802, --- Postgresql data type of type jsonb.
  • BITEA = 17, --- Postgresql data type of type bitea.
  • POINT = 600, --- Postgresql data type of type point.
  • BOX = 603, --- Postgresql data type of type box.
  • LSEG = 601, --- Postgresql data type of type lseg.
  • LINE = 628, --- Postgresql data type of type line.
  • CIRCLE = 718 --- Postgresql data type of type circle.

NOTE: Not all PostgreSQL data types are supported by PostgreSQLClient, but will be in a future release with a PostgreSQL to native GDscript type conversion table in the documentation.

Property Descriptions

  • float PROTOCOL_VERSION const

Default value: 3.0

Version number (minor.major) of the PostgreSQL protocol used when connecting to the backend

  • dictionary parameter_status reader alone

Default value: {}

A dictionary that contains various information about the execution state of the server. For security reasons the dictionary is always empty if the frontend is disconnected from the backend and updates once the connection is established.

Noted that the server is free to return whatever value it wants. Always remember to check the presence of the key before accessing the associated value.

Example of a typical value that a backend might return. Values may differ depending on the backend:

{"DateStyle":"ISO, DMY", "IntervalStyle":"postgres", "TimeZone":"Europe/Paris", "application_name":"", "client_encoding":"UTF8", "integer_datetimes":"on", "is_superuser":"off", "server_encoding":"UTF8", "server_version":"12.7 (Ubuntu 12.7-0ubuntu0.20.04.1)", "session_authorization":"samuel", "standard_conforming_strings":"on"}

Method Descriptions

  • Error connect_to_host(url: String, ssl: bool = false, connect_timeout: int = 30)

Allows you to connect to a Postgresql backend at the specified url.

The url parameter is a PostgreSQL URL ideally in the form "postgresql://user:password@host:port/databasename". All other PostgreSQL URL syntaxes specified in this page [https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING] are not yet fully supported.

Noted that the default port for PostgreSQL is 5432.

The ssl parameter is unstable, therefore do not pass to true. The problem will be fixed in the future version.

  • Array execute(sql: String)

Allows to send an SQL string to the backend that should run. The sql parameter can contain one or more valid SQL statements. Returns an Array of PostgreSQLQueryResult. There are as many PostgreSQLQueryResult elements in the array as there are SQL statements in sql (sof in exceptional cases).

  • void rollback(process_id : int, process_key : int)

Do not use because it is too unstable, will be subject to modification in future versions.

  • void close(clean_closure: bool = true)

Allows you to close the connection with the backend. If clean_closure is true, the frontend will notify the backend that it requests to close the connection. If false, the frontend forcibly closes the connection without notifying the backend (not recommended sof in exceptional cases).

Has no effect if the frontend is not already connected to the backend.

  • void set_ssl_connection()

Not working at the moment, don't use it. will be subject to change in future versions.

Signal Descriptions

  • connection_closed(was_clean_close: bool)

Fires when the connection to the backend closes. was_clean_close is true if the connection was closed correctly otherwise false.

  • connection_error()

Do not listen to this signal, does not work. will be subject to change see removed in future versions.

  • connection_established()

Trigger when the connection between the frontend and the backend is established. This is usually a good time to start making requests to the backend with execute ().

DOCUMENTATION PostgreSQLQueryResult (NON FINALISÉE):

Descriptions

The PostgreSQLQueryResult class is a subclass of PostgreSQLClient which is not intended to be created manually. It represents the result of an SQL query and provides an information and method report to use the result of the query. It is usually returned by the PostgreSQLClient.execute() method in an array of PostgreSQLQueryResult.

PROPERTIES:

Type Properties Default value
int number_of_fields_in_a_row const 0
Array row_description const []
Array data_row const []
String command_tag const ""

METHODS:

Type Method
Array get_field_values(field_name: String)
PostgreSQLClient.DataTypePostgreSQL field_data_type(field_name: String)

Property Descriptions int number_of_fields_in_a_row const

Default value: 0

Specifies the number of fields in a row (can be zero).

Array row_description const

Default value: []

An array that contains dictionaries. these dictionaries represent the description of the rows where the query was executed. The number of dictionary depends on the number of fields resulting from the result of the query which was executed.

Each dictionary is structured like this:

{
	"field_name": field_name,
	"table_object_id": table_object_id,
	"column_index": column_index,
	"type_object_id": type_object_id,
	"data_type_size": data_type_size,
	"type_modifier": type_modifier,
	"format_code": format_code
}
  • Where the field_name value is a string that represents the name of the field.
  • Where the value table object_id is an int which represents the identifier of the table object whether the field can be identified as a column from a specific table; otherwise 0.
  • Where the column_index value is an int which represents the attribute number of the column if the field can be identified as a column from a specific table; otherwise zero.
  • Where the type_object_id value is an PostgreSQLClient.DataTypePostgreSQL which represents the object ID of the data type of the field.
  • Where the data_type_size value is an int which represents the size of the data type. Note: that negative values indicate variable width types.
  • Where the type_modifier value is an int which represents the type modifier. Note: The meaning of the modifier is type specific.
  • Where the format_code value is an int which represents the format code used for the field. Currently will be 0 (text) or 1 (binary). In a RowDescription returned by the instruction variant of Describe, the format code is not yet known and will always be zero. This value is low-level PostgreSQL protocol information that is not useful in most cases. You can ignore this value.

Array data_row const

Default value: []

An Array that contains sub-arrays. these sub-arrays represent for most of the queries the rows of the table where the query was executed. The number of sub-tables depends on the query that has been made. These sub-arrays contain as many elements as number_of_fields_in_a_row. These elements are native GDscript types that represent the data resulting from the query.

Example return value:

[[1, "Hello my id is 1"], [2, "Hello my id is 2"], [3, "Hello my id is 3"]]

There are 3 rows. Each row contains the value of 2 fields: The row identifier and a character string.

/!\ At the moment, it doesn't only return native types! this will be the case in the future version! this is one of the first mistakes I made while writing PostgreSQLClient. /!\

String command_tag const

Default value: ""

This is usually a single word that identifies which SQL command was completed.

Method Descriptions

Array get_field_values(field_name: String)

Returns all the values of a field. field_name is the name of the field on which we get the values. Can be empty if the field name is unknown. The field_name parameter is case sensitive.

PostgreSQLClient.DataTypePostgreSQL field_data_type(field_name: String)

Returns the object ID of the data type of the field. field_name is the name of the field whose type we get. Can return -1 if the field name is unknown. The field_name parameter is case sensitive.

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