An OracleBFile is an object that has a reference to BFILE data. It provides methods for performing operations on BFILEs.
|
Note: OracleBFile is supported for applications running against Oracle8.x and later. |
Class Inheritance
Object
MarshalByRefObject
Stream
OracleBFile
Declaration
// C# public sealed class OracleBFile : Stream, ICloneable
Thread Safety
All public static methods are thread-safe, although instance methods do not guarantee thread safety.
Remarks
OracleBFile is supported for applications running against Oracle8.x and later.
Example
// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
*/
// C#
using System;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
class OracleBFileSample
{
static void Main()
{
// Create MYDIR directory object as indicated previously and create a file
// MyFile.txt with the text ABCDABC under C:\TEMP directory.
// Note that the byte representation of the ABCDABC is 65666768656667
string constr = "User Id=scott;Password=tiger;Data Source=oracle";
OracleConnection con = new OracleConnection(constr);
con.Open();
OracleBFile bFile = new OracleBFile(con, "MYDIR", "MyFile.txt");
// Open the OracleBFile
bFile.OpenFile();
// Read 7 bytes into readBuffer, starting at buffer offset 0
byte[] readBuffer = new byte[7];
int bytesRead = bFile.Read(readBuffer, 0, 7);
// Prints "bytesRead = 7"
Console.WriteLine("bytesRead = " + bytesRead);
// Prints "readBuffer = 65666768656667"
Console.Write("readBuffer = ");
for(int index = 0; index < readBuffer.Length; index++)
{
Console.Write(readBuffer[index]);
}
Console.WriteLine();
// Search for the 2nd occurrence of a byte pattern {66,67}
// starting from byte offset 1 in the OracleBFile
byte[] pattern = new byte[2] {66, 67};
long posFound = bFile.Search(pattern, 1, 2);
// Prints "posFound = 6"
Console.WriteLine("posFound = " + posFound);
// Close the OracleBFile
bFile.CloseFile();
bFile.Close();
bFile.Dispose();
con.Close();
con.Dispose();
}
}
Requirements
Namespace: Oracle.DataAccess.Types
Assembly: Oracle.DataAccess.dll
OracleBFile members are listed in the following tables:
OracleBFile Constructors
OracleBFile constructors are listed in Table 10-1.
Table 10-1 OracleBFile Constructors
| Constructor | Description |
|---|---|
| OracleBFile Constructors | Creates an instance of the OracleBFile class (Overloaded) |
OracleBFile Static Fields
OracleBFile static fields are listed in Table 10-2.
Table 10-2 OracleBFile Static Fields
| Field | Description |
|---|---|
| MaxSize | The static field holds the maximum number of bytes a BFILE can hold, which is 4,294,967,295 (2^32 - 1) bytes |
OracleBFile Static Methods
OracleBFile static methods are listed in Table 10-3.
OracleBFile Instance Properties
OracleBFile instance properties are listed in Table 10-4.
Table 10-4 OracleBFile Instance Properties
| Properties | Description |
|---|---|
| CanRead | Indicates whether or not the LOB stream can be read |
| CanSeek | Indicates whether or not forward and backward seek operations can be performed |
| CanWrite | Indicates whether or not the LOB object supports writing |
| Connection | Indicates the connection used to read from a BFILE |
| DirectoryName | Indicates the directory alias of the BFILE |
| FileExists | Indicates whether or not the specified BFILE exists |
| FileName | Indicates the name of the BFILE |
| IsEmpty | Indicates whether the BFILE is empty or not |
| IsOpen | Indicates whether the BFILE has been opened by this instance or not |
| Length | Indicates the size of the BFILE data in bytes |
| Position | Indicates the current read position in the LOB stream |
| Value | Returns the data, starting from the first byte in BFILE, as a byte array |
OracleBFile Instance Methods
OracleBFile instance methods are listed in Table 10-5.
Table 10-5 OracleBFile Instance Methods
| Methods | Description |
|---|---|
BeginRead |
Inherited from Stream |
BeginWrite |
Not Supported |
| Clone | Creates a copy of an OracleBFile object |
| Close | Closes the current stream and releases any resources associated with the stream |
| CloseFile | Closes the BFILE referenced by the current BFILE instance |
| Compare | Compares data referenced by the two OracleBFiles |
CreateObjRef |
Inherited from MarshalByRefObject |
| CopyTo | Copies data as specified (Overloaded) |
| Dispose | Releases resources allocated by this object |
EndRead |
Inherited from Stream |
EndWrite |
Not Supported |
Equals |
Inherited from Object (Overloaded) |
Flush |
Not Supported |
GetHashCode |
Inherited from Object |
GetLifetimeService |
Inherited from MarshalByRefObject |
GetType |
Inherited from Object |
InitializeLifetimeService |
Inherited from MarshalByRefObject |
| IsEqual | Compares the LOB references |
| OpenFile | Opens the BFILE specified by the FileName and DirectoryName |
| Read | Reads a specified amount of bytes from the OracleBFile instance and populates the buffer |
ReadByte |
Inherited from Stream |
| Search | Searches for a binary pattern in the current instance of an OracleBFile |
| Seek | Sets the position on the current LOB stream |
SetLength |
Not Supported |
ToString |
Inherited from Object |
Write |
Not Supported |
WriteByte |
Not Supported |
OracleBFile constructors create new instances of the OracleBFile class.
Overload List:
This constructor creates an instance of the OracleBFile class with an OracleConnection object.
OracleBFile(OracleConnection, string, string)
This constructor creates an instance of the OracleBFile class with an OracleConnection object, the location of the BFILE, and the name of the BFILE.
This constructor creates an instance of the OracleBFile class with an OracleConnection object.
Declaration
// C#
public OracleBFile(OracleConnection con);
Parameters
con
The OracleConnection object.
Exceptions
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
The connection must be opened explicitly by the application. OracleBFile does not open the connection implicitly.
This constructor creates an instance of the OracleBFile class with an OracleConnection object, the location of the BFILE, and the name of the BFILE.
Declaration
// C# public OracleBFile(OracleConnection con, string directoryName, string fileName);
Parameters
con
The OracleConnection object.
directoryName
The directory alias created by the CREATE DIRECTORY SQL statement.
fileName
The name of the external LOB.
Exceptions
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
The OracleConnection must be opened explicitly by the application. OracleBFile does not open the connection implicitly.
To initialize a BFILE column using an OracleBFile instance as an input parameter of a SQL INSERT statement, directoryName and fileName must be properly set.
OracleBFile static fields are listed in Table 10-6.
Table 10-6 OracleBFile Static Fields
| Field | Description |
|---|---|
| MaxSize | The static field holds the maximum number of bytes a BFILE can hold, which is 4,294,967,295 (2^32 - 1) bytes |
This static field holds the maximum number of bytes a BFILE can hold, which is 4,294,967,295 (2^32 - 1) bytes.
Declaration
// C# public static readonly Int64 MaxSize = 4294967295;
Remarks
This field is useful in code that checks whether or not the operation exceeds the maximum length allowed.
OracleBFile static methods are listed in Table 10-7.
OracleBFile instance properties are listed in Table 10-8.
Table 10-8 OracleBFile Instance Properties
| Properties | Description |
|---|---|
| CanRead | Indicates whether or not the LOB stream can be read |
| CanSeek | Indicates whether or not forward and backward seek operations can be performed |
| CanWrite | Indicates whether or not the LOB object supports writing |
| Connection | Indicates the connection used to read from a BFILE |
| DirectoryName | Indicates the directory alias of the BFILE |
| FileExists | Indicates whether or not the specified BFILE exists |
| FileName | Indicates the name of the BFILE |
| IsEmpty | Indicates whether the BFILE is empty or not |
| IsOpen | Indicates whether the BFILE has been opened by this instance or not |
| Length | Indicates the size of the BFILE data in bytes |
| Position | Indicates the current read position in the LOB stream |
| Value | Returns the data, starting from the first byte in BFILE, as a byte array |
Overrides Stream
This instance property indicates whether or not the LOB stream can be read.
Declaration
// C#
public override bool CanRead{get;}
Property Value
If the LOB stream can be read, returns true; otherwise, returns false.
Overrides Stream
This instance property indicates whether or not forward and backward seek operations can be performed.
Declaration
// C#
public override bool CanSeek{get;}
Property Value
If forward and backward seek operations can be performed, returns true; otherwise, returns false.
Overrides Stream
This instance property indicates whether or not the LOB object supports writing.
Declaration
// C#
public override bool CanWrite{get;}
Property Value
BFILE is read only.
Remarks
BFILE is read-only, therefore, the boolean value is always false.
This instance property indicates the connection used to read from a BFILE.
Declaration
// C#
public OracleConnection Connection {get;}
Property Value
An object of OracleConnection.
Exceptions
ObjectDisposedException - The object is already disposed.
This instance property indicates the directory alias of the BFILE.
Declaration
// C#
public string DirectoryName {get;set;}
Property Value
A string.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The value of the DirectoryName changed while the BFILE is open.
Remarks
The maximum length of a DirectoryName is 30 bytes.
This instance property indicates whether or not the BFILE specified by the DirectoryName and FileName exists.
Declaration
// C#
public bool FileExists {get;}
Property Value
bool
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
Unless a connection, file name, and directory name are provided, this property is set to false by default.
This instance property indicates the name of the BFILE.
Declaration
// C#
public string FileName {get;set}
Property Value
A string that contains the BFILE name.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The value of the DirectoryName changed while the BFILE is open.
Remarks
The maximum length of a FileName is 255 bytes.
Changing the FileName property while the BFILE object is opened causes an exception.
This instance property indicates whether the BFILE is empty or not.
Declaration
// C#
public bool IsEmpty {get;}
Property Value
bool
Exceptions
ObjectDisposedException - The object is already disposed.
This instance property indicates whether the BFILE has been opened by this instance or not.
Declaration
// C#
public bool IsOpen {get;}
Property Value
A bool.
Overrides Stream
This instance property indicates the size of the BFILE data in bytes.
Declaration
// C#
public override Int64 Length {get;}
Property Value
Int64
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Overrides Stream
This instance property indicates the current read position in the LOB stream.
Declaration
// C#
public override Int64 Position{get; set;}
Property Value
An Int64 value that indicates the read position.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
ArgumentOutOfRangeException - The value is less than 0.
This instance property returns the data, starting from the first byte in BFILE, as a byte array.
Declaration
// C#
public byte[] Value{get;}
Property Value
A byte array.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
The length of data is bound by the maximum length of the byte array. The current value of the Position property is not used or changed.
OracleBFile instance methods are listed in Table 10-9.
Table 10-9 OracleBFile Instance Methods
| Methods | Description |
|---|---|
BeginRead |
Inherited from Stream |
BeginWrite |
Not Supported |
| Clone | Creates a copy of an OracleBFile object |
| Close | Closes the current stream and releases any resources associated with the stream |
| CloseFile | Closes the BFILE referenced by the current BFILE instance |
| Compare | Compares data referenced by the two OracleBFiles |
CreateObjRef |
Inherited from MarshalByRefObject |
| CopyTo | Copies data as specified (Overloaded) |
| Dispose | Releases resources allocated by this object |
EndRead |
Inherited from Stream |
EndWrite |
Not Supported |
Equals |
Inherited from Object (Overloaded) |
Flush |
Not Supported |
GetHashCode |
Inherited from Object |
GetLifetimeService |
Inherited from MarshalByRefObject |
GetType |
Inherited from Object |
InitializeLifetimeService |
Inherited from MarshalByRefObject |
| IsEqual | Compares the LOB references |
| OpenFile | Opens the BFILE specified by the FileName and DirectoryName |
| Read | Reads a specified amount of bytes from the OracleBFile instance and populates the buffer |
ReadByte |
Inherited from Stream |
| Search | Searches for a binary pattern in the current instance of an OracleBFile |
| Seek | Sets the position on the current LOB stream |
SetLength |
Not Supported |
ToString |
Inherited from Object |
Write |
Not Supported |
WriteByte |
Not Supported |
This instance method creates a copy of an OracleBFile object.
Declaration
// C# public object Clone();
Return Value
An OracleBFile object.
Implements
ICloneable
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
The cloned object has the same property values as that of the object being cloned.
Example
// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
*/
// C#
using System;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
class CloneSample
{
static void Main()
{
// Create MYDIR directory object as indicated previously and create a file
// MyFile.txt with the text ABCDABC under C:\TEMP directory.
// Note that the byte representation of the ABCDABC is 65666768656667
string constr = "User Id=scott;Password=tiger;Data Source=oracle";
OracleConnection con = new OracleConnection(constr);
con.Open();
OracleBFile bFile1 = new OracleBFile(con, "MYDIR", "MyFile.txt");
// Prints "bFile1.Position = 0"
Console.WriteLine("bFile1.Position = " + bFile1.Position);
// Set the Position before calling Clone()
bFile1.Position = 1;
// Clone the OracleBFile
OracleBFile bFile2 = (OracleBFile) bFile1.Clone();
// Prints "bFile2.Position = 1"
Console.WriteLine("bFile2.Position = " + bFile2.Position);
bFile1.Close();
bFile1.Dispose();
bFile2.Close();
bFile2.Dispose();
con.Close();
con.Dispose();
}
}
Overrides Stream
This instance method closes the current stream and releases any resources associated with it.
Declaration
// C# public override void Close();
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
This instance method closes the BFILE referenced by the current BFILE instance.
Declaration
// C# public void CloseFile();
Remarks
No error is returned if the BFILE exists, but is not opened.
This instance method compares data referenced by the two OracleBFiles.
Declaration
// C# public int Compare(Int64 src_offset, OracleBFile obj, Int64 dst_offset, Int64 amount);
Parameters
src_offset
The offset of the current instance.
obj
The provided OracleBFile object.
dst_offset
The offset of the OracleBFile object.
amount
The number of bytes to compare.
Return Value
Returns a number that is:
Less than zero: if the BFILE data of the current instance is less than that of the provided BFILE data.
Zero: if both the BFILEs store the same data.
Greater than zero: if the BFILE data of the current instance is greater than that of the provided BFILE data.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
ArgumentOutOfRangeException - The src_offset, the dst_offset, or the amount is less than 0.
Remarks
The provided object and the current instance must be using the same connection, that is, the same OracleConnection object.
The BFILE needs to be opened using OpenFile before the operation.
Example
// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
*/
// C#
using System;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
class CompareSample
{
static void Main()
{
// Create MYDIR directory object as indicated previously and create a file
// MyFile.txt with the text ABCDABC under C:\TEMP directory.
// Note that the byte representation of the ABCDABC is 65666768656667
string constr = "User Id=scott;Password=tiger;Data Source=oracle";
OracleConnection con = new OracleConnection(constr);
con.Open();
OracleBFile bFile1 = new OracleBFile(con, "MYDIR", "MyFile.txt");
OracleBFile bFile2 = new OracleBFile(con, "MYDIR", "MyFile.txt");
// Open the OracleBFiles
bFile1.OpenFile();
bFile2.OpenFile();
// Compare 2 bytes from the 1st byte of bFile1 and
// the 5th byte of bFile2 onwards
int result = bFile1.Compare(1, bFile2, 5, 2);
// Prints "result = 0" (Indicates the data is identical)
Console.WriteLine("result = " + result);
// Close the OracleBFiles
bFile1.CloseFile();
bFile2.CloseFile();
bFile1.Close();
bFile1.Dispose();
bFile2.Close();
bFile2.Dispose();
con.Close();
con.Dispose();
}
}
CopyTo copies data from the current instance to the provided object.
Overload List:
This instance method copies data from the current instance to the provided OracleBlob object.
This instance method copies data from the current OracleBFile instance to the provided OracleBlob object with the specified destination offset.
CopyTo(Int64, OracleBlob, Int64, Int64)
This instance method copies data from the current OracleBFile instance to the provided OracleBlob object with the specified source offset, destination offset, and character amounts.
This instance method copies data from the current OracleBFile instance to the provided OracleClob object.
This instance method copies data from the current OracleBFile instance to the provided OracleClob object with the specified destination offset.
CopyTo(Int64, OracleClob, Int64, Int64)
This instance method copies data from the current OracleBFile instance to the provided OracleClob object with the specified source offset, destination offset, and amount of characters.
This instance method copies data from the current instance to the provided OracleBlob object.
Declaration
// C#
public Int64 CopyTo(OracleBlob obj);
Parameters
obj
The OracleBlob object to which the data is copied.
Return Value
The return value is the amount copied.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - This exception is thrown if any of the following conditions exist:
The OracleConnection is not open or has been closed during the lifetime of the object.
The LOB object parameter has a different connection than the object.
Remarks
The provided object and the current instance must be using the same connection; that is, the same OracleConnection object.
This instance method copies data from the current OracleBFile instance to the provided OracleBlob object with the specified destination offset.
Declaration
// C# public Int64 CopyTo(OracleBlob obj, Int64 dst_offset);
Parameters
obj
The OracleBlob object to which the data is copied.
dst_offset
The offset (in bytes) at which the OracleBlob object is copied.
Return Value
The return value is the amount copied.
Exceptions
ObjectDisposedException - The object is already disposed.
ArgumentOutOfRangeException - The dst_offset is less than 0.
InvalidOperationException - This exception is thrown if any of the following conditions exist:
The OracleConnection is not open or has been closed during the lifetime of the object.
The LOB object parameter has a different connection than the object.
Remarks
If the dst_offset is beyond the end of the OracleBlob data, spaces are written into the OracleBlob until the dst_offset is met.
The offsets are 0-based. No character conversion is performed by this operation.
The provided object and the current instance must be using the same connection; that is, the same OracleConnection object.
This instance method copies data from the current OracleBFile instance to the provided OracleBlob object with the specified source offset, destination offset, and character amounts.
Declaration
// C# public Int64 CopyTo(Int64 src_offset,OracleBlob obj,Int64 dst_offset, Int64 amount);
Parameters
src_offset
The offset (in bytes) in the current instance, from which the data is read.
obj
An OracleBlob object to which the data is copied.
dst_offset
The offset (in bytes) to which the OracleBlob object is copied.
amount
The amount of data to be copied.
Return Value
The return value is the amount copied.
Exceptions
ObjectDisposedException - The object is already disposed.
ArgumentOutOfRangeException - The src_offset, the dst_offset, or the amount is less than 0.
InvalidOperationException - This exception is thrown if any of the following conditions exist:
The OracleConnection is not open or has been closed during the lifetime of the object.
The LOB object parameter has a different connection than the object.
Remarks
If the dst_offset is beyond the end of the OracleBlob data, spaces are written into the OracleBlob until the dst_offset is met.
The offsets are 0-based. No character conversion is performed by this operation.
The provided object and the current instance must be using the same connection; that is, the same OracleConnection object.
This instance method copies data from the current OracleBFile instance to the provided OracleClob object.
Declaration
// C#
public Int64 CopyTo(OracleClob obj);
Parameters
obj
The OracleClob object to which the data is copied.
Return Value
The return value is the amount copied.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - This exception is thrown if any of the following conditions exist:
The OracleConnection is not open or has been closed during the lifetime of the object.
The LOB object parameter has a different connection than the object.
Remarks
The provided object and the current instance must be using the same connection, that is, the same OracleConnection object.
This instance method copies data from the current OracleBFile instance to the provided OracleClob object with the specified destination offset.
Declaration
// C# public Int64 CopyTo(OracleClob obj, Int64 dst_offset);
Parameters
obj
The OracleClob object that the data is copied to.
dst_offset
The offset (in characters) at which the OracleClob object is copied to.
Return Value
The amount copied.
Exceptions
Exceptions
ObjectDisposedException - The object is already disposed.
ArgumentOutOfRangeException - The dst_offset is less than 0.
InvalidOperationException - This exception is thrown if any of the following conditions exist:
The OracleConnection is not open or has been closed during the lifetime of the object.
The LOB object parameter has a different connection than the object.
Remarks
If the dst_offset is beyond the end of the OracleClob data, spaces are written into the OracleClob until the dst_offset is met.
The offsets are 0-based. No character conversion is performed by this operation.
The provided object and the current instance must be using the same connection, that is, the same OracleConnection object.
This instance method copies data from the current OracleBFile instance to the provided OracleClob object with the specified source offset, destination offset, and amount of characters.
Declaration
// C# public Int64 CopyTo(Int64 src_offset,OracleClob obj,Int64 dst_offset, Int64 amount);
Parameters
src_offset
The offset (in characters) in the current instance, from which the data is read.
obj
An OracleClob object that the data is copied to.
dst_offset
The offset (in characters) at which the OracleClob object is copied to.
amount
The amount of data to be copied.
Return Value
The return value is the amount copied.
Exceptions
ObjectDisposedException - The object is already disposed.
ArgumentOutOfRangeException - The src_offset, the dst_offset, or the amount is less than 0.
InvalidOperationException - This exception is thrown if any of the following conditions exist:
The OracleConnection is not open or has been closed during the lifetime of the object.
The LOB object parameter has a different connection than the object.
Remarks
If the dst_offset is beyond the end of the current OracleClob data, spaces are written into the OracleClob until the dst_offset is met.
The offsets are 0-based. No character conversion is performed by this operation.
The provided object and the current instance must be using the same connection, that is, the same OracleConnection object.
This instance method releases resources allocated by this object.
Declaration
// C# public void Dispose();
Implements
IDisposable
Remarks
Although some properties can still be accessed, their values may not be accountable. Since resources are freed, method calls may lead to exceptions. The object cannot be reused after being disposed.
This instance method compares the LOB references.
Declaration
// C#
public bool IsEqual(OracleBFile obj);
Parameters
obj
The provided OracleBFile object.
Return Value
Returns true if the current OracleBFile and the provided OracleBFile object refer to the same external LOB. Returns false otherwise.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
Note that this method can return true even if the two OracleBFile objects return false for == or Equals() since two different OracleBFile instances can refer to the same external LOB.
The provided object and the current instance must be using the same connection; that is, the same OracleConnection object.
This instance method opens the BFILE specified by the FileName and DirectoryName.
Declaration
// C# public void OpenFile();
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
Many operations, such as Compare(), CopyTo(), Read(), and Search() require that the BFILE be opened using OpenFile before the operation.
Calling OpenFile on an opened BFILE is not operational.
Overrides Stream
This instance method reads a specified amount of bytes from the OracleBFile instance and populates the buffer.
Declaration
// C# public override int Read(byte[ ] buffer, int offset, int count);
Parameters
buffer
The byte array buffer to be populated.
offset
The offset of the byte array buffer to be populated.
count
The amount of bytes to read.
Return Value
The return value indicates the number of bytes read from the BFILE, that is, the external LOB.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
ArgumentOutOfRangeException - Either the offset or the count parameter is less than 0 or the offset is greater than or equal to the buffer.Length or the offset and the count together are greater than buffer.Length.
Remarks
The LOB data is read starting from the position specified by the Position property.
Example
// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
*/
// C#
using System;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
class ReadSample
{
static void Main()
{
// Create MYDIR directory object as indicated previously and create a file
// MyFile.txt with the text ABCDABC under C:\TEMP directory.
// Note that the byte representation of the ABCDABC is 65666768656667
string constr = "User Id=scott;Password=tiger;Data Source=oracle";
OracleConnection con = new OracleConnection(constr);
con.Open();
OracleBFile bFile = new OracleBFile(con, "MYDIR", "MyFile.txt");
// Open the OracleBFile
bFile.OpenFile();
// Read 7 bytes into readBuffer, starting at buffer offset 0
byte[] readBuffer = new byte[7];
int bytesRead = bFile.Read(readBuffer, 0, 7);
// Prints "bytesRead = 7"
Console.WriteLine("bytesRead = " + bytesRead);
// Prints "readBuffer = 65666768656667"
Console.Write("readBuffer = ");
for(int index = 0; index < readBuffer.Length; index++)
{
Console.Write(readBuffer[index]);
}
Console.WriteLine();
// Close the OracleBFile
bFile.CloseFile();
bFile.Close();
bFile.Dispose();
con.Close();
con.Dispose();
}
}
This instance method searches for a binary pattern in the current instance of an OracleBFile.
Declaration
// C# public int Search(byte[ ] val, Int64 offset, Int64 nth);
Parameters
val
The binary pattern being searched for.
offset
The 0-based offset (in bytes) starting from which the OracleBFile is searched.
nth
The specific occurrence (1-based) of the match for which the offset is returned.
Return Value
Returns the absolute offset of the start of the matched pattern (in bytes) for the nth occurrence of the match. Otherwise, 0 is returned.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
ArgumentOutOfRangeException - Either the offset is less than 0 or nth is less than or equal to 0 or val.Length is greater than 16383 or nth is greater than or equal to OracleBFile.MaxSize or offset is greater than or equal to OracleBFile.MaxSize.
Remarks
The limit of the search pattern is 16383 bytes.
Example
// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
*/
// C#
using System;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
class SearchSample
{
static void Main()
{
// Create MYDIR directory object as indicated previously and create a file
// MyFile.txt with the text ABCDABC under C:\TEMP directory.
// Note that the byte representation of the ABCDABC is 65666768656667
string constr = "User Id=scott;Password=tiger;Data Source=oracle";
OracleConnection con = new OracleConnection(constr);
con.Open();
OracleBFile bFile = new OracleBFile(con, "MYDIR", "MyFile.txt");
// Open the OracleBFile
bFile.OpenFile();
// Search for the 2nd occurrence of a byte pattern {66,67}
// starting from byte offset 1 in the OracleBFile
byte[] pattern = new byte[2] {66, 67};
long posFound = bFile.Search(pattern, 1, 2);
// Prints "posFound = 6"
Console.WriteLine("posFound = " + posFound);
// Close the OracleBFile
bFile.CloseFile();
bFile.Close();
bFile.Dispose();
con.Close();
con.Dispose();
}
}
Overrides Stream
This instance method sets the position on the current LOB stream.
Declaration
// C# public override Int64 Seek(Int64 offset, SeekOrigin origin);
Parameters
offset
A byte offset relative to origin.
origin
A value of type System.IO.SeekOrigin indicating the reference point used to obtain the new position.
Return Value
Returns an Int64 that indicates the position.
Exceptions
ObjectDisposedException - The object is already disposed.
InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.
Remarks
If offset is negative, the new position precedes the position specified by origin by the number of bytes specified by offset.
If offset is zero, the new position is the position specified by origin.
If offset is positive, the new position follows the position specified by origin by the number of bytes specified by offset.
SeekOrigin.Begin specifies the beginning of a stream.
SeekOrigin.Current specifies the current position within a stream.
SeekOrigin.End specifies the end of a stream.
Example
// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
*/
// C#
using System;
using System.IO;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
class SeekSample
{
static void Main()
{
// Create MYDIR directory object as indicated previously and create a file
// MyFile.txt with the text ABCDABC under C:\TEMP directory.
// Note that the byte representation of the ABCDABC is 65666768656667
string constr = "User Id=scott;Password=tiger;Data Source=oracle";
OracleConnection con = new OracleConnection(constr);
con.Open();
OracleBFile bFile = new OracleBFile(con, "MYDIR", "MyFile.txt");
// Open the OracleBFile
bFile.OpenFile();
// Set the Position to 2 with respect to SeekOrigin.Begin
long newPosition = bFile.Seek(2, SeekOrigin.Begin);
// Prints "newPosition = 2"
Console.WriteLine("newPosition = " + newPosition);
// Prints "bFile.Position = 2"
Console.WriteLine("bFile.Position = " + bFile.Position);
// Read 2 bytes into readBuffer, starting at buffer offset 1
byte[] readBuffer = new byte[4];
int bytesRead = bFile.Read(readBuffer, 1, 2);
// Prints "bytesRead = 2"
Console.WriteLine("bytesRead = " + bytesRead);
// Prints "readBuffer = 067680"
Console.Write("readBuffer = ");
for(int index = 0; index < readBuffer.Length; index++)
{
Console.Write(readBuffer[index]);
}
Console.WriteLine();
// Close the OracleBFile
bFile.CloseFile();
bFile.Close();
bFile.Dispose();
con.Close();
con.Dispose();
}
}