PostgreSQL接口编程一：OLEDB－－PGNP驱动
1介绍PGNP Native Provider是以OLEDB接口访问PostgreSQL数据库的驱动程序。以下简称PGNP，PostgreSQL数据库以下简称pg。
PGNP是pg数据库的OLEDB接口驱动程序，他介于微软OLEDB和ADO.NET之OLEDB与PostgreSQL libpq库接口之间，实现了大多数OLEDB接口，并使用pg的libpq访问pg数据库。PGNP可以为.NET和NATIVE的32/64位应用程序提供支持访问pg。
这是一个商业软件，Business license要390$。
从http://pgoledb.com/可以下载使用版PGNP-1.3.0.2251.exe
2安装
点击PGNP-1.3.0.2251.exe开始安装，按下一步即可完成。
3用psql连到postgreSQL，psql中命令 \i sql_script_file_name即可
sql_script_file_name文件中内容如下：
--建模式、表、插入记录、建函数
-- Create schema for PGNP samples
-- DROP SCHEMA pgnp_samples;
CREATE SCHEMA pgnp_samples AUTHORIZATION postgres;
GRANT ALL ON SCHEMA pgnp_samples TO postgres;
SET search_path='pgnp_samples';
--删除photo类型字段
-- DROP TABLE pgnp_samples.contact;
CREATE TABLE contact
(
contact_id bigint not null,
fname character varying(64),
lname character varying(64),
revenue double precision,
-- photo lo,
created_date timestamp without time zone NOT NULL DEFAULT now(),
modified_date timestamp without time zone NOT NULL DEFAULT now(),
CONSTRAINT pk_contact_id PRIMARY KEY (contact_id)
);
INSERT INTO contact(contact_id, fname, lname, revenue) VALUES (1, 'James', 'Smith', 20000.0), (2, 'Sue', 'McMartin', 35000.0);
-- DROP TABLE pgnp_samples."group";
CREATE TABLE "group"
(
group_id bigint not null,
group_name character varying(128),
region uuid,
created_date timestamp without time zone NOT NULL DEFAULT now(),
modified_date timestamp without time zone NOT NULL DEFAULT now(),
CONSTRAINT pk_group_id PRIMARY KEY (group_id)
);
INSERT INTO "group"(group_id, group_name, region) VALUES (1, 'EMEA', '00000000000000000000000000000001'), (2, 'NA', '00000000000000000000000000000002');
-- DROP FUNCTION pgnp_samples.ContactsLike(character varying(64));
CREATE OR REPLACE FUNCTION ContactsLike(character varying(64)) RETURNS bigint AS 'SELECT count(1) FROM contact WHERE lname ~~* $1;' LANGUAGE SQL;
--as后边加空格
DROP FUNCTION pgnp_samples.sptest2(integer);
CREATE OR REPLACE FUNCTION pgnp_samples.sptest2(IN integer)
RETURNS TABLE(f1 integer, f2 text) AS
$BODY$
SELECT $1, CAST($1 AS text) || ' is text'
UNION ALL
SELECT $1*2, CAST($1 AS text) || ' is text too'
$BODY$
LANGUAGE 'sql';
-- DROP FUNCTION pgnp_samples.GetMultipleResults();
CREATE OR REPLACE FUNCTION GetMultipleResults() RETURNS SETOF refcursor AS
'DECLARE refContact refcursor; refGroup refcursor;
BEGIN
OPEN refContact FOR SELECT * FROM contact; RETURN NEXT refContact;
OPEN refGroup FOR SELECT * FROM "group"; RETURN NEXT refGroup;
RETURN;
END;' LANGUAGE plpgsql;
-- DROP TABLE arrays
CREATE TABLE arrays
(
id serial NOT NULL,
test1d character varying(15)[],
test2d numeric(7,3)[][],
test3d integer[][][],
CONSTRAINT pk_arrays_id PRIMARY KEY (id)
);
INSERT INTO arrays(test1d, test2d, test3d)
VALUES('{"New York", Paris, Bejing}', '{{3000.146,17.101,0.000,0.667},{3.14159,2.71,-1.778,128.3}}',
'{{3,16,9,22,15,0,100},{20,8,21,14,2,0,100},{7,25,13,1,19,0,100},{24,12,5,18,6,0,100},{11,4,17,10,23,0,100}}')
4. C#代码如下：
public partial class Program
{
static readonly string connStr = "Provider=PGNP.1;Data Source=localhost;Initial Catalog=postgres;User ID=postgres;Password=12345;Extended Properties=\"NESTED_TRANS=ON;SEARCH_PATH=pgnp_samples,public;PORT=5432\"";
static int Main(string[] args)
{
int error_count = 0;
error_count += Get_Arrays();
if (error_count > 0)
ConsoleWriteError("Errors count: " + error_count, "");
else
ConsoleWriteSuccess("All samples ran successfully!");
return error_count;
}
static void ConsoleWriteSampleHeader(String sample_hdr)
{
Console.ForegroundColor = ConsoleColor.Blue;
Console.WriteLine(sample_hdr);
}
static void ConsoleWriteMessage(String msg)
{
ConsoleWriteMessage(msg, " ");
}
static void ConsoleWriteMessage(String msg, String blank)
{
Console.ForegroundColor = ConsoleColor.Gray;
Console.WriteLine(blank + msg);
}
static void ConsoleWriteError(String error, String optionalStmt)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine("** " + error);
if (optionalStmt.Length > 0)
{
Console.ForegroundColor = ConsoleColor.Gray;
Console.WriteLine(" Last stmt: " + optionalStmt);
}
}
static void ConsoleWriteSuccess(String success_msg)
{
Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine(success_msg);
}
static public int Get_Arrays()
{
String lastStmt = "";
try
{
OleDbConnection conn = new OleDbConnection(connStr);
conn.Open();
// Read records from pgnp_samples.contact table.
ConsoleWriteSampleHeader("Reading array elements from database.");
OleDbCommand cmd = conn.CreateCommand();
cmd.CommandText = lastStmt = "SELECT test1d, test2d, test3d FROM arrays";
OleDbDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
for (int fieldIndex = 0; fieldIndex < 3; fieldIndex++)
{
if (dr.IsDBNull(fieldIndex))
{
ConsoleWriteMessage(String.Format("{0}: ", dr.GetName(fieldIndex)));
continue;
}
PrintArrayElements(dr.GetName(fieldIndex), dr.GetValue(fieldIndex) as Array);
}
}
}
catch (Exception ex)
{
ConsoleWriteError(ex.Message, lastStmt);
return 1;
}
return 0;
}
static public void PrintArrayElements(string fieldName, Array field)
{
ConsoleWriteMessage(fieldName + ":", " ");
switch (field.Rank)
{
case 1:
for (int i = field.GetLowerBound(0); i < field.GetLowerBound(0) + field.GetLength(0); i++)
{
object x = field.GetValue(i);
ConsoleWriteMessage(String.Format("{0}>{1}", i, x));
}
break;
case 2:
for (int j = field.GetLowerBound(1); j < field.GetLowerBound(1) + field.GetLength(1); j++)
{
for (int i = field.GetLowerBound(0); i < field.GetLowerBound(0) + field.GetLength(0); i++)
{
object x = field.GetValue(i, j);
ConsoleWriteMessage(String.Format("({0},{1}) > {2}", i, j, x));
}
}
break;
case 3:
for (int k = field.GetLowerBound(2); k < field.GetLowerBound(2) + field.GetLength(2); k++)
{
for (int j = field.GetLowerBound(1); j < field.GetLowerBound(1) + field.GetLength(1); j++)
{
for (int i = field.GetLowerBound(0); i < field.GetLowerBound(0) + field.GetLength(0); i++)
{
object x = field.GetValue(i, j, k);
ConsoleWriteMessage(String.Format("({0},{1},{2}) > {3}", i, j, k, x));
}
}
}
break;
}
}
}
5.执行结果如下：
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