|
|
You're in the
dotnet remoting
group:Binary Serialization -- how to actually insert into database?
dotnet remoting:
ive read some good articles on the tenents of serialization and when & why youd want to do it, as well as the types. great! now id like to put it to practice. however....none of the articles i found had database examples -- all were files. how do i insert a memory stream into the database? (im currently usesing oracle, so this would be into a table w/ a CLOB column). heres what i have so far: DataTable someData = GetData(); MemoryStream stream = new MemoryStream(); BinaryFormatter formatter = new BinaryFormatter(); formatter.Serialize(stream, someData); ....thanks for the tips or links. matt
[quoted text, click to view]
Patrick Steele wrote: > Use the MemoryStream.ToArray() method to get a byte[]. You should be > able to stick that in your CLOB column. thanks. im guessing thats what i have to do...clob takes in characters up to 4gb. theres a BLOB datatype that takes a binary object up to 4gb as well. but ive not serialized before so im not up to speed on which to use. i see theres also a .ToString() method on the stream. any idea what the difference is between working w/ a byte array vs a string? i know i can pass the string into oracle's CLOB; i dont know yet about the array. thanks, matt
ah.. looks like the byte array is what meshes w/ the binary data
stream, so BLOB is what should be used. tests work, good to go. thanks, matt
In article <1161881651.151886.219760@f16g2000cwb.googlegroups.com>,
matt@mailinator.com says... [quoted text, click to view] > hey all, > > ive read some good articles on the tenents of serialization and when & > why youd want to do it, as well as the types. great! > > now id like to put it to practice. however....none of the articles i > found had database examples -- all were files. how do i insert a memory > stream into the database? (im currently usesing oracle, so this would > be into a table w/ a CLOB column). > > heres what i have so far: > > > DataTable someData = GetData(); > > MemoryStream stream = new MemoryStream(); > > BinaryFormatter formatter = new BinaryFormatter(); > formatter.Serialize(stream, someData); > > > ...thanks for the tips or links. > Use the MemoryStream.ToArray() method to get a byte[]. You should be able to stick that in your CLOB column. -- Patrick Steele
Hi Matt,
[quoted text, click to view] > i see theres also a .ToString() method on the stream. any idea what the > difference is between working w/ a byte array vs a string? i know i can > pass the string into oracle's CLOB; i dont know yet about the array. MemoryStream inherits ToString from System.Object, but it doesn't override the inherited behavior. Therefore, ToString will only return the full Type name of the object - in this case, "System.IO.MemoryStream". To retrieve the contents of a MemoryStream you should use the ToArray method, as suggested by Patrick. And yes you are correct that BLOB corresponds with binary data, which is the contents of your MemoryStream and the output of the ToArray method, so it doesn't make sense to use a character data type in your database. -- Dave Sexton [quoted text, click to view] <matt@mailinator.com> wrote in message news:1161887313.837108.311990@m73g2000cwd.googlegroups.com... > Patrick Steele wrote: >> Use the MemoryStream.ToArray() method to get a byte[]. You should be >> able to stick that in your CLOB column. > > thanks. im guessing thats what i have to do...clob takes in characters > up to 4gb. theres a BLOB datatype that takes a binary object up to 4gb > as well. but ive not serialized before so im not up to speed on which > to use. > > i see theres also a .ToString() method on the stream. any idea what the > difference is between working w/ a byte array vs a string? i know i can > pass the string into oracle's CLOB; i dont know yet about the array. > > > thanks, > matt >
[quoted text, click to view]
matt@mailinator.com wrote: > hey all, > > now id like to put it to practice. however....none of the articles i > found had database examples -- all were files. how do i insert a memory > stream into the database? (im currently usesing oracle, so this would > be into a table w/ a CLOB column). make sense to store binary data in database? The database is the right place in order to do data warehouse, reporting and so on not a container of all.
Hi Tommaso,
[quoted text, click to view] > The database is the right place in order to do data warehouse, reporting and > so on not a container of all. Unless it's a relational database, of course. Just to cite a few examples, ASP.NET session state or the ASP.NET 2.0 provider infrastructure data such as membership and roles are commonly stored today in Microsoft Sql Server, a well known RDBMS. This shows that databases aren't only for data warehousing and reporting. Session State Modes on MSDN: http://msdn2.microsoft.com/en-us/library/ms178586.aspx Configuring ASP.NET 2.0 Application Services to Use SQL Server 2000 / 2005 on MSDN: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnaspp/html/configaspnet_sql.asp [quoted text, click to view] > make sense to store binary data in database? Serialization into Sql Server, for example, provides relational storage for the binary data, which is otherwise usually controlled by a file-numbering system outside of the database. This method of relational persistence isn't enforced by simple database constraints that ensure the integrity of the data, but instead only by your code - if done correctly. If each file, commonly graphical images, are to be saved in reference to a primary key in a database then it makes sense in some circumstances to just store the data in the database row along with the related data. Controlling the serialization of an object and storing it in the database is a flexible alternative to other persistence mechanism and can be used in WinForms and web apps to persist complex object graphs without having to write some proprietary xml schema or file-numbering system that introduces the possibility for more bugs and requires you to author I/O, which databases handle for you efficiently, behind the scenes. Xml object graphs could be used instead to provide a more flexible alternative to binary serialization. Sql Server supports xpath to query the serialized structure, in place. Using XPath Queries on MSDN: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/xmlsql/ac_mschema_3gab.asp?frame=true -- Dave Sexton [quoted text, click to view] "Tommaso Caldarola" <ilbecchino@lcimitero.it> wrote in message news:4543105f$1_2@x-privat.org... > matt@mailinator.com wrote: >> hey all, >> >> now id like to put it to practice. however....none of the articles i >> found had database examples -- all were files. how do i insert a memory >> stream into the database? (im currently usesing oracle, so this would >> be into a table w/ a CLOB column). > > make sense to store binary data in database? > > The database is the right place in order to do data warehouse, reporting and > so on not a container of all. >
Talk about timely...
I'm actually trying to do this with SQL. I'm trying to store business objects for auditing purposes, so that I don't have to mess around with the format of various different types, I want to serialize and store the entire object. I'm getting a deserialize error from the following code: Private Shared Function DeHydrateAnObject(ByVal this As Object) As String Dim UE As New UnicodeEncoding Dim m As System.IO.MemoryStream = New System.IO.MemoryStream Dim b As System.Runtime.Serialization.Formatters.Binary.BinaryFormatter = New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter b.Serialize(m, this) Return UE.GetString(m.ToArray) End Function Public Shared Function HydrateAnObject(ByVal this As String, ByVal strType As String) As Object Dim UE As New UnicodeEncoding Dim m As System.IO.MemoryStream = New System.IO.MemoryStream(UE.GetBytes(this)) Dim b As System.Runtime.Serialization.Formatters.Binary.BinaryFormatter = New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter 'Dim thisType As Type = Type.GetType(strType) Return CType(b.Deserialize(m), Product) End Function For now, it's hard coded as a "Product" My question is, for SQL 2000, what database type should I use? The field is NText right now, but I get the following on the deserialize Binary stream does not contain a valid BinaryHeader, 0 possible causes, invalid stream or object version change between serialization and deserialization
Dave,
The DAO code where I work is all stored in one huge class file. I didn't want any confusion between my serialization code and the .NET method(s) #1 and #2, I've been using nHibernate on other projects, so the Dehydrate thing is a little bit burned into my retina at the moment :-) Thanks for the answer so quick. Helps to know I'm on the right track. [quoted text, click to view] "Dave Sexton" wrote:
> Hi, > > You will want to use varbinary or image, depending on the size of your > objects. varbinary can go up to 8000 bytes, IIRC. The large character types > text and ntext are not binary, they are text, so unless you're using a > SoapFormatter or XmlSerializer they won't be of much use to you here. > > If you could use the added flexibility of searching the object graph from > within the database itself using Sql Server's built-in xml support then using > the text column type and serializing the object with an XmlSerializer might be > a better choice for you. > > Just out of curiosity, why did you choose the term "dehydrate" over > "serialize" and "hydrate" over "deserialize"? > > IMO, your code will make more sense if you describe the methods for what they > are actually doing using framework idioms such as "serialize" and > "deserialize". > > -- > Dave Sexton > > "pirho" <pirho@discussions.microsoft.com> wrote in message > news:3962F0D4-E2E3-4684-B474-8295C4F8AF9C@microsoft.com... > > Talk about timely... > > > > I'm actually trying to do this with SQL. I'm trying to store business > > objects for auditing purposes, so that I don't have to mess around with the > > format of various different types, I want to serialize and store the entire > > object. > > > > I'm getting a deserialize error from the following code: > > > > Private Shared Function DeHydrateAnObject(ByVal this As Object) As String > > Dim UE As New UnicodeEncoding > > Dim m As System.IO.MemoryStream = New System.IO.MemoryStream > > Dim b As > > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter = New > > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter > > b.Serialize(m, this) > > Return UE.GetString(m.ToArray) > > End Function > > > > Public Shared Function HydrateAnObject(ByVal this As String, ByVal > > strType As String) As Object > > Dim UE As New UnicodeEncoding > > Dim m As System.IO.MemoryStream = New > > System.IO.MemoryStream(UE.GetBytes(this)) > > Dim b As > > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter = New > > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter > > 'Dim thisType As Type = Type.GetType(strType) > > Return CType(b.Deserialize(m), Product) > > End Function > > > > > > For now, it's hard coded as a "Product" > > > > My question is, for SQL 2000, what database type should I use? > > The field is NText right now, but I get the following on the deserialize > > > > Binary stream does not contain a valid BinaryHeader, 0 possible causes, > > invalid stream or object version change between serialization and > > deserialization > > > > Very new to the serialization stuff, so any ideas would be appreciated. > >
Hi,
You will want to use varbinary or image, depending on the size of your objects. varbinary can go up to 8000 bytes, IIRC. The large character types text and ntext are not binary, they are text, so unless you're using a SoapFormatter or XmlSerializer they won't be of much use to you here. If you could use the added flexibility of searching the object graph from within the database itself using Sql Server's built-in xml support then using the text column type and serializing the object with an XmlSerializer might be a better choice for you. Just out of curiosity, why did you choose the term "dehydrate" over "serialize" and "hydrate" over "deserialize"? IMO, your code will make more sense if you describe the methods for what they are actually doing using framework idioms such as "serialize" and "deserialize". -- Dave Sexton [quoted text, click to view] "pirho" <pirho@discussions.microsoft.com> wrote in message news:3962F0D4-E2E3-4684-B474-8295C4F8AF9C@microsoft.com... > Talk about timely... > > I'm actually trying to do this with SQL. I'm trying to store business > objects for auditing purposes, so that I don't have to mess around with the > format of various different types, I want to serialize and store the entire > object. > > I'm getting a deserialize error from the following code: > > Private Shared Function DeHydrateAnObject(ByVal this As Object) As String > Dim UE As New UnicodeEncoding > Dim m As System.IO.MemoryStream = New System.IO.MemoryStream > Dim b As > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter = New > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter > b.Serialize(m, this) > Return UE.GetString(m.ToArray) > End Function > > Public Shared Function HydrateAnObject(ByVal this As String, ByVal > strType As String) As Object > Dim UE As New UnicodeEncoding > Dim m As System.IO.MemoryStream = New > System.IO.MemoryStream(UE.GetBytes(this)) > Dim b As > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter = New > System.Runtime.Serialization.Formatters.Binary.BinaryFormatter > 'Dim thisType As Type = Type.GetType(strType) > Return CType(b.Deserialize(m), Product) > End Function > > > For now, it's hard coded as a "Product" > > My question is, for SQL 2000, what database type should I use? > The field is NText right now, but I get the following on the deserialize > > Binary stream does not contain a valid BinaryHeader, 0 possible causes, > invalid stream or object version change between serialization and > deserialization > > Very new to the serialization stuff, so any ideas would be appreciated.
Don't see what you're looking for? Try a search.
|
June 2003
July 2003
August 2003
September 2003
October 2003
November 2003
December 2003
January 2004
February 2004
March 2004
April 2004
May 2004
June 2004
July 2004
August 2004
September 2004
October 2004
November 2004
December 2004
January 2005
February 2005
March 2005
April 2005
May 2005
June 2005
July 2005
August 2005
September 2005
October 2005
November 2005
December 2005
January 2006
February 2006
March 2006
April 2006
May 2006
June 2006
July 2006
August 2006
September 2006
October 2006
November 2006
December 2006
January 2007
February 2007
March 2007
April 2007
May 2007
June 2007
July 2007
August 2007
September 2007
October 2007
November 2007
December 2007
January 2008
February 2008
March 2008
April 2008
May 2008
June 2008
| home · blog · groups | Questions? Comments? Contact the dn |