.. index:: 
	single: PostgreSQL; はじめに

===============
PostgreSQL 関数
===============

PostgreSQL データベースの用法を学びます。

.. index:: 
	pair: PostgreSQL; ライブラリの読み込み

ライブラリの読み込み
====================

この関数の使用前に postgresqllib.ring ライブラリを読み込みます。

.. code-block:: ring

	load "postgresqllib.ring"
	# PostgreSQL 関数の使用

.. index:: 
	pair: PostgreSQL; 用例

用例
====

用例 (1):

.. code-block:: ring

		load "postgresqllib.ring"

		conninfo = "user=postgres password=sa dbname = postgres"

		exit_nicely = func conn {
			PQfinish(conn)
			shutdown(1)
		}

		conn = PQconnectdb(conninfo)

		if (PQstatus(conn) != CONNECTION_OK)
			fputs(stderr, "Connection to database failed: "+PQerrorMessage(conn))
				call exit_nicely(conn)
		ok

		res = PQexec(conn, "select * from pg_database")
		if PQresultStatus(res) != PGRES_TUPLES_OK
			fputs(stderr, "Select failed: " + PQerrorMessage(conn))
			PQclear(res)
			exit_nicely(conn)
		ok

		nFields = PQnfields(res)
		for i = 1 to nFields
				? PQfname(res, i-1) 
		next

		? copy("*",60)

		for i = 1 to PQntuples(res)
			for j=1 to nFields
				see PQgetvalue(res, i-1, j-1) + " "
			next
			see nl
		next

		PQclear(res)

		PQfinish(conn)

実行結果:

.. code-block:: none 

	datname
	datdba
	encoding
	datcollate
	datctype
	datistemplate
	datallowconn
	datconnlimit
	datlastsysoid
	datfrozenxid
	datminmxid
	dattablespace
	datacl
	************************************************************
	postgres 10 6 English_United States.1252 
		English_United States.1252 f t -1 12937 549 1 1663
	template1 10 6 English_United States.1252 English_United States.1252 
		t t -1 12937 549 1 1663 {=c/postgres,postgres=CTc/postgres}
	template0 10 6 English_United States.1252 English_United States.1252 
		t f -1 12937 549 1 1663 {=c/postgres,postgres=CTc/postgres}
	mahdb 10 6 English_United States.1252 English_United States.1252 
		f t -1 12937 549 1 1663
		
用例 (2):

.. code-block:: ring

	load "postgresqllib.ring"

	conninfo = "user=postgres password=sa dbname = mahdb"

	exit_nicely = func conn {
		PQfinish(conn)
		shutdown(1)
	}

	conn = PQconnectdb(conninfo)

	if (PQstatus(conn) != CONNECTION_OK)
		fputs(stderr, "Connection to database failed: "+PQerrorMessage(conn))
			call exit_nicely(conn)
	ok

	res = PQexec(conn, "
		DROP DATABASE mahdb;
	")
	if PQresultStatus(res) != PGRES_TUPLES_OK
		fputs(stderr, "Remove failed: " + PQerrorMessage(conn))
		PQclear(res)
	ok
	PQclear(res)


	res = PQexec(conn, "CREATE DATABASE mahdb;")
	if PQresultStatus(res) != PGRES_TUPLES_OK
		fputs(stderr, "Create database failed: " + PQerrorMessage(conn))
		PQclear(res)
	ok


	res = PQexec(conn, "
	CREATE TABLE COMPANY (
			 ID INT PRIMARY KEY     NOT NULL,
			 NAME           TEXT    NOT NULL,
			 AGE            INT     NOT NULL,
			 ADDRESS        CHAR(50),
			 SALARY         REAL );
	")
	if PQresultStatus(res) != PGRES_TUPLES_OK
		fputs(stderr, "Create Table failed: " + PQerrorMessage(conn))
		PQclear(res)
	ok
	PQclear(res)

	res = PQexec(conn, "
			INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
			VALUES  (1, 'Mahmoud' , 31, 'Jeddah', 10.00 ),
					(2, 'Ahmed'   , 27, 'Jeddah', 20.00 ),
					(3, 'Mohammed', 33, 'Egypt' , 30.00 ),
					(4, 'Ibrahim' , 24, 'Egypt ', 40.00 );
	")
	if PQresultStatus(res) != PGRES_TUPLES_OK
		fputs(stderr, "Insert Table failed: " + PQerrorMessage(conn))
		PQclear(res)
	ok
	PQclear(res)

	res = PQexec(conn, "
		   select * from COMPANY
	")
	if PQresultStatus(res) != PGRES_TUPLES_OK
		fputs(stderr, "Select failed: " + PQerrorMessage(conn))
		PQclear(res)
		call exit_nicely(conn)
	ok


	nFields = PQnfields(res)
	for i = 1 to nFields
			? PQfname(res, i-1) 
	next

	? copy("*",60)

	for i = 1 to PQntuples(res)
		for j=1 to nFields
			see PQgetvalue(res, i-1, j-1) + " "
		next
		see nl
	next

	PQclear(res)

	PQfinish(conn)

実行結果:

.. code-block:: none

	id
	name
	age
	address
	salary
	************************************************************
	1 Mahmoud  31 Jeddah  10
	2 Ahmed    27 Jeddah  20
	3 Mohammed 31 Egypt   30
	4 Ibrahim  24 Egypt   40	
	

.. index:: 
	pair: PostgreSQL; RingPostgreSQL 定数

RingPostgreSQL 定数
===================

この定数は RingPostgreSQL ライブラリで定義済みです。

.. code-block:: none

	CONNECTION_STARTED
	CONNECTION_MADE
	CONNECTION_AWAITING_RESPONSE
	CONNECTION_AUTH_OK
	CONNECTION_SSL_STARTUP
	CONNECTION_SETENV
	CONNECTION_OK

	PQPING_OK
	PQPING_REJECT
	PQPING_NO_RESPONSE
	PQPING_NO_ATTEMPT

	PGRES_EMPTY_QUERY
	PGRES_COMMAND_OK
	PGRES_TUPLES_OK
	PGRES_COPY_OUT
	PGRES_COPY_IN
	PGRES_BAD_RESPONSE
	PGRES_NONFATAL_ERROR
	PGRES_FATAL_ERROR
	PGRES_COPY_BOTH
	PGRES_SINGLE_TUPLE

	PG_DIAG_SEVERITY
	PG_DIAG_SQLSTATE
	PG_DIAG_MESSAGE_PRIMARY
	PG_DIAG_MESSAGE_DETAIL
	PG_DIAG_MESSAGE_HINT
	PG_DIAG_STATEMENT_POSITION
	PG_DIAG_INTERNAL_POSITION
	PG_DIAG_INTERNAL_QUERY
	PG_DIAG_CONTEXT
	PG_DIAG_SCHEMA_NAME
	PG_DIAG_TABLE_NAME
	PG_DIAG_COLUMN_NAME
	PG_DIAG_DATATYPE_NAME
	PG_DIAG_CONSTRAINT_NAME
	PG_DIAG_SOURCE_FILE
	PG_DIAG_SOURCE_LINE
	PG_DIAG_SOURCE_FUNCTION


.. index:: 
	pair: PostgreSQL; RingPostgreSQL 関数

RingPostgreSQL 関数
===================

この関数は RingPostgreSQL ライブラリで定義されています。

リファレンス : https://www.postgresql.org/docs/9.1/static/libpq.html

.. code-block:: none

	PGconn *PQconnectdbParams(const char **keywords,
		const char **values,int expand_dbname);
	PGconn *PQconnectdb(const char *conninfo)
	PGconn *PQsetdbLogin(const char *pghost,const char *pgport,
		const char *pgoptions,const char *pgtty,
		const char *dbName,const char *login,const char *pwd)
	PGconn *PQsetdb(char *pghost,char *pgport,char *pgoptions,
		char *pgtty,char *dbName)
	PGconn *PQconnectStartParams(const char **keywords,
		const char **values,int expand_dbname)
	PGconn *PQconnectStart(const char *conninfo)
	PostgresPollingStatusType PQconnectPoll(PGconn *conn)
	PQconninfoOption *PQconndefaults(void)
	PQconninfoOption *PQconninfo(PGconn *conn)
	PQconninfoOption *PQconninfoParse(const char *conninfo, char **errmsg)
	void PQfinish(PGconn *conn)
	void PQreset(PGconn *conn)
	int PQresetStart(PGconn *conn)
	PostgresPollingStatusType PQresetPoll(PGconn *conn)
	PGPing PQpingParams(const char **keywords,const char **values,
		int expand_dbname)
	PGPing PQping(const char *conninfo)
	char *PQdb(const PGconn *conn)
	char *PQuser(const PGconn *conn)
	char *PQpass(const PGconn *conn)
	char *PQhost(const PGconn *conn)
	char *PQport(const PGconn *conn)
	char *PQtty(const PGconn *conn)
	char *PQoptions(const PGconn *conn)
	ConnStatusType PQstatus(const PGconn *conn)
	PGTransactionStatusType PQtransactionStatus(const PGconn *conn)
	const char *PQparameterStatus(const PGconn *conn, const char *paramName)
	int PQprotocolVersion(const PGconn *conn)
	int PQserverVersion(const PGconn *conn)
	char *PQerrorMessage(const PGconn *conn)
	int PQsocket(const PGconn *conn)
	int PQbackendPID(const PGconn *conn)
	int PQconnectionNeedsPassword(const PGconn *conn)
	int PQconnectionUsedPassword(const PGconn *conn)
	int PQsslInUse(const PGconn *conn)
	const char *PQsslAttribute(const PGconn *conn, const char *attribute_name)
	const char **PQsslAttributeNames(const PGconn *conn)
	void *PQsslStruct(const PGconn *conn, const char *struct_name)
	void *PQgetssl(const PGconn *conn)
	PGresult *PQexec(PGconn *conn, const char *command);
	PGresult *PQexecParams(PGconn *conn,const char *command,int nParams,
		const Oid *paramTypes,const char **paramValues,
		const int *paramLengths,const int *paramFormats,int resultFormat)
	PGresult *PQprepare(PGconn *conn,const char *stmtName,
		const char *query,int nParams,const Oid *paramTypes)
	PGresult *PQexecPrepared(PGconn *conn,const char *stmtName,
		int nParams,const char **paramValues,
		const int *paramLengths,const int *paramFormats,int resultFormat)
	PGresult *PQdescribePrepared(PGconn *conn, const char *stmtName)
	PGresult *PQdescribePortal(PGconn *conn, const char *portalName)
	ExecStatusType PQresultStatus(const PGresult *res)
	char *PQresStatus(ExecStatusType status)
	char *PQresultErrorMessage(const PGresult *res)
	char *PQresultErrorField(const PGresult *res, int fieldcode)
	void PQclear(PGresult *res)
	int PQntuples(const PGresult *res)
	int PQnfields(const PGresult *res)
	char *PQfname(const PGresult *res,int column_number)
	int PQfnumber(const PGresult *res,const char *column_name)
	Oid PQftable(const PGresult *res,int column_number)
	int PQftablecol(const PGresult *res,int column_number)
	int PQfformat(const PGresult *res,int column_number)
	Oid PQftype(const PGresult *res,int column_number)
	int PQfmod(const PGresult *res,int column_number)
	int PQfsize(const PGresult *res,int column_number)
	int PQbinaryTuples(const PGresult *res)
	char *PQgetvalue(const PGresult *res,int row_number,int column_number)
	int PQgetisnull(const PGresult *res,int row_number,int column_number)
	int PQgetlength(const PGresult *res,int row_number,int column_number)
	int PQnparams(const PGresult *res)
	Oid PQparamtype(const PGresult *res, int param_number)
	void PQprint(FILE *fout,const PGresult *res,const PQprintOpt *po)
	char *PQcmdStatus(PGresult *res)
	char *PQcmdTuples(PGresult *res)
	Oid PQoidValue(const PGresult *res)
	char *PQoidStatus(const PGresult *res)
	char *PQescapeLiteral(PGconn *conn, const char *str, size_t length)
	char *PQescapeIdentifier(PGconn *conn, const char *str, size_t length)
	size_t PQescapeStringConn(PGconn *conn,char *to, 
		const char *from, size_t length,int *error)
	size_t PQescapeString(char *to, const char *from, size_t length)
	unsigned char *PQescapeByteaConn(PGconn *conn,
		const unsigned char *from,size_t from_length,size_t *to_length)
	unsigned char *PQescapeBytea(const unsigned char *from,
		size_t from_length,size_t *to_length)
	unsigned char *PQunescapeBytea(const unsigned char *from, size_t *to_length)
	int PQsendQuery(PGconn *conn, const char *command)
	int PQsendQueryParams(PGconn *conn,const char *command,
		int nParams,const Oid *paramTypes,const char **paramValues,
		const int *paramLengths,const int *paramFormats,int resultFormat)
	int PQsendPrepare(PGconn *conn,const char *stmtName,
		const char *query,int nParams,const Oid *paramTypes)
	int PQsendQueryPrepared(PGconn *conn,const char *stmtName,
		int nParams,const char **paramValues,
		const int *paramLengths,const int *paramFormats,int resultFormat)
	int PQsendDescribePrepared(PGconn *conn, const char *stmtName)
	int PQsendDescribePortal(PGconn *conn, const char *portalName)
	PGresult *PQgetResult(PGconn *conn)
	int PQconsumeInput(PGconn *conn)
	int PQisBusy(PGconn *conn)
	int PQsetnonblocking(PGconn *conn, int arg)
	int PQisnonblocking(const PGconn *conn)
	int PQflush(PGconn *conn)
	int PQsetSingleRowMode(PGconn *conn)
	PGcancel *PQgetCancel(PGconn *conn)
	void PQfreeCancel(PGcancel *cancel)
	int PQcancel(PGcancel *cancel, char *errbuf, int errbufsize)
	int PQrequestCancel(PGconn *conn)
	PGresult *PQfn(PGconn *conn,int fnid,int *result_buf,
		int *result_len,int result_is_int,const PQArgBlock *args,int nargs)
	PGnotify *PQnotifies(PGconn *conn)
	int PQputCopyData(PGconn *conn,const char *buffer,int nbytes)
	int PQputCopyEnd(PGconn *conn,const char *errormsg)
	int PQgetCopyData(PGconn *conn,char **buffer,int async)
	int PQgetline(PGconn *conn,char *buffer,int length)
	int PQgetlineAsync(PGconn *conn,char *buffer,int bufsize)
	int PQputline(PGconn *conn,const char *string)
	int PQputnbytes(PGconn *conn,const char *buffer,int nbytes)
	int PQendcopy(PGconn *conn)
	int PQclientEncoding(const PGconn *conn)
	char *pg_encoding_to_char(int encoding_id)
	int PQsetClientEncoding(PGconn *conn, const char *encoding)
	void PQtrace(PGconn *conn, FILE *stream)
	void PQuntrace(PGconn *conn)
	void PQfreemem(void *ptr)
	void PQconninfoFree(PQconninfoOption *connOptions)
	char *PQencryptPasswordConn(PGconn *conn, const char *passwd,
		 const char *user, const char *algorithm)
	char *PQencryptPassword(const char *passwd, const char *user)
	PGresult *PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status)
	int PQfireResultCreateEvents(PGconn *conn, PGresult *res)
	PGresult *PQcopyResult(const PGresult *src, int flags)
	int PQsetResultAttrs(PGresult *res, int numAttributes, PGresAttDesc *attDescs)
	int PQsetvalue(PGresult *res, int tup_num, int field_num, 
			char *value, int len)
	void *PQresultAlloc(PGresult *res, size_t nBytes)
	int PQlibVersion(void)
	PQnoticeReceiver PQsetNoticeReceiver(PGconn *conn,
			PQnoticeReceiver proc,void *arg)
	PQnoticeProcessor PQsetNoticeProcessor(PGconn *conn,
			PQnoticeProcessor proc,void *arg)
	void PQinitOpenSSL(int do_ssl, int do_crypto)
	void PQinitSSL(int do_ssl)
	int PQisthreadsafe(void)
