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PostgreSQL and binary data [message #20333]

Thu, 12 March 2009 01:05

Kajko
Messages: 14
Registered: December 2008
Location: Ireland, Serbia

Promising Member

Hi,

Can anyone tell me/give me example code Smile

of how to store/read binary data from PostgreSQL and what type of field is needed.
Data size will vary from 50k to 5MB.

Thanks,
Sasa

b78a07c7fb9b68436af9fd23f4e76cc5

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Re: PostgreSQL and binary data [message #20335 is a reply to message #20333]

Thu, 12 March 2009 11:23

phirox
Messages: 49
Registered: December 2007

Member

You can just use the data field name BLOB or LONGRAW in your schema. These are both of the type 'bytea' in pgsql. And can be filled with a normal String in upp. Since Strings can contain any raw data(including '\000') this shouldn't provide any problem.

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Re: PostgreSQL and binary data [message #20346 is a reply to message #20333]

Thu, 12 March 2009 20:45

unodgs
Messages: 1367
Registered: November 2005
Location: Poland

Ultimate Contributor

Kajko wrote on Wed, 11 March 2009 20:05

Hi,

Can anyone tell me/give me example code Smile

of how to store/read binary data from PostgreSQL and what type of field is needed.
Data size will vary from 50k to 5MB.

Thanks,
Sasa

I use..

String ToBytea(const String& s)
{
	size_t rl;
	PostgreSQLSession &pses = (PostgreSQLSession &) SQL.GetSession();
	unsigned char *sb = PQescapeByteaConn(pses.GetPGConn(), (const byte *) ~s, s.GetLength(), &rl);
	String k(sb, rl + 16);
	PQfreemem(sb);
	return k;
}

to save binary data. Of course field type in database is also bytea.
For example:

SQL & ::Insert(DESCRIPTION_PICTURE)
	(DESCRIPTION_ID, id)
	(DESCRIPTION, data.desc)
	(BIG_PICTURE, ToBytea(encoder.SaveString(data.oryginal)))
	(SMALL_PICTURE, ToBytea(encoder.SaveString(data.resized)));

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Re: PostgreSQL and binary data [message #20393 is a reply to message #20333]

Mon, 16 March 2009 13:15

Kajko
Messages: 14
Registered: December 2008
Location: Ireland, Serbia

Promising Member

Works

thank you all very much.

Sasa

b78a07c7fb9b68436af9fd23f4e76cc5

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Re: PostgreSQL and binary data [message #24363 is a reply to message #20346]

Tue, 12 January 2010 20:29

marroyo
Messages: 8
Registered: August 2009
Location: Argentina

Promising Member

How can I to save and load binary data (png images) with postgresql?

I can save (i think) but I can't load.

Thanks in advance.

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Re: PostgreSQL and binary data [message #24403 is a reply to message #24363]

Thu, 14 January 2010 17:03

mirek
Messages: 14255
Registered: November 2005

Ultimate Member

Situation has improved a bit, you now have this option:

SQL * Insert(IMAGE)(DATA, SqlBinary(imagedata));

For loading, you do not have to do anything. Just fetch it to String.

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