Structure of a Record which has a text column - sql-server-2005

I have a record which I viewed using DBCC page command. Here is how it looks:
Memory Dump #0x00E5C060
00000000: 30000800 01000000 02000001 001f8000 †0...............
00000010: 00d10700 0000009a 00000001 000000††††...............
Slot 0 Column 0 Offset 0x4 Length 4
col1 = 1
col2 = [Textpointer] Slot 0 Column 1 Offset 0xf Length 16
TextTimeStamp = 131137536 RowId = (1:154:0)
Here col1 is of type int and col2 is of type ntext.
I know that ntext column values are stored in text page.
But I don't know how to interpret col2 info above, i.e.
col2 = [Textpointer] Slot 0 Column 1 Offset 0xf Length 16
TextTimeStamp = 131137536 RowId = (1:154:0)
Can anybody help me understand this?
Thanks for replying,
"col2 = [Textpointer] Slot 0 Column 1 Offset 0xf Length 16"
00000000: 30000800 01000000 02000001 001f8000 †0...............
00000010: 00d10700 0000009a 00000001 000000††††...............
In this, it's said that the length of info is 16.
Its equivalent hex values are:
00 00d10700 0000009a 00000001 000000†††
I can find information about
TextTimeStamp = 131137536 RowId = (1:154:0)
in the above hex values. But how can I find info that it is a text pointer?
Moreover, in another instance, I came across [Inline Blob root] for an nvarchar datatype value.
Here's how it looked:
col6= [BLOB Inline Root] Slot 1 Column 38 Offset 0x16d Length 24
Level = 0 Unused = 0 UpdateSeq = 1
TimeStamp = 1969553408
Link 0
Here if you notice the length is 24 in contrast to the previous instance (Text pointer)
It has some additional information as well like update sequence is
UpdateSeq = 1.
How can I differentiate between the two instances by looking at the sequence of bytes?

col2 is a pointer to the BLOB allocation unit. The ntext column is on slot 0 on the page (1:154). You can DBCC dump the page 1:154 to find the content of the ntext column col2.
There is a more detailed example at http://blogs.msdn.com/sqlserverstorageengine/archive/2006/12/13/More-undocumented-fun_3A00_-DBCC-IND_2C00_-DBCC-PAGE_2C00_-and-off_2D00_row-columns.aspx

Related

How to process mainframe numbers where "{" is the last character

I have a one mainframe file data like as below
000000720000{
I need to parse the data and load into a hive table like below
72000
the above field is income column and "{" sign which denotes +ve amount
datatype used while creating table income decimal(11,2)
in layout.cob copybook using INCOME PIC S9(11)V99
could someone help?
The number you want is 7200000 which would be 72000.00.
The conversion you are looking for is:
Positive numbers
{ = 0
A = 1
B = 2
C = 3
D = 4
E = 5
F = 6
G = 7
H = 8
I = 9
Negative numbers (this makes the whole value negative)
} = 0
J = 1
K = 2
L = 3
M = 4
N = 5
O = 6
P = 7
Q = 8
R = 9
Let's explain why.
Based on your question the issue you are having is when packed decimal data is unpacked UNPK into character data. Basically, the PIC S9(11)V2 actually takes up 7 bytes of storage and looks like the picture below.
You'll see three lines. The top is the character representation (missing in the first picture because the hex values do not map to displayable characters) and the lines below are the hexadecimal values. Most significant digit on top and least below.
Note that in the rightmost byte the sign is stored as C which is positive, to represent a negative value you would see a D.
When it is converted to character data it will look like this
Notice the C0 which is a consequence of the unpacking to preserve the sign. Be aware that this display is on z/OS which is EBCDIC. If the file has been transferred and converted to another code-page you will see the correct character but the hex values will be different.
Here are all the combinations you will likely see for positive numbers
and here for negative numbers
To make your life easy, if you see one of the first set of characters then you can replace it with the corresponding number. If you see something from the second set then it is a negative number.

Aligning numeric values on left with WRITE

I'm creating a calculation table and want to align the numbers on the left under the '+'.
But somehow the first number in each column from the counter has some space before it.
How can I eliminate that space and align my table so that the left side is all in one row?
Code:
DATA: counter TYPE i,
counter2 TYPE i.
ULINE /(159).
WRITE: /1 sy-vline , '+', sy-vline.
DO 11 TIMES.
counter = sy-index - 1 .
WRITE: counter, sy-vline.
ENDDO.
ULINE /(159).
DO 11 TIMES.
counter = sy-index - 1 .
WRITE: /1 sy-vline , counter , sy-vline.
ULINE /(159).
ENDDO.
The spaces in front of the number are there because of the data type. Type i is an elementary data type and can have numbers from -2147483648 to 2147483647, which means it can be 11 characters long. Some data types have an output length that is variable, but that is not the case for i. You can see that if you click on it in your output, it should have a red outline 11 characters long.
But if you would rather have the spaces at the end of the number, then you can use 'CONVERSION_EXIT_ALPHA_OUTPUT'. But the "table outline" will still have to be just as big, since the number can have 11 characters.
DATA: counterc TYPE c LENGTH 11.
...
MOVE counter TO counterc.
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
EXPORTING
input = counterc
IMPORTING
output = counterc.
...
WRITE: ... counterc ...
Alternatively, the output of a table looks way better if you use SALV. Look here for example, to see how to output a table using SALV.

ISO 8583 Field 22

I'm trying to build an parser to deserialze into object. Socket will send byte into parser. For the length of field 22 POS Entry Mode will N3 and byte will be always 2 digit. How to get the value for this field ?
You read the ASCII value of this field, and convert it into an integer.
if it says N3 that means they are three digits numeric field, so if the value say 51, you cast it to 051 and send the ASCII equivalent
Field 22 is pos entry mode. It's 3 digit numeric value. If format is BCD then 2 bytes contains 4 digits[ 0 (padded) + 3 digit POS entry mode). If format is ascci then it is 3 byte.

Rasterizing Paths data from Photoshop file

I was able to read the paths data from a Photoshop file.Photoshop File Format. The curves bezier curves. I want to convert this data into pixel format. How do i do this?.
Read thouroughly the documentation given On the Adobe's Website. I separated the data as 26 byte records.
Let's say one of the record is as follows
0 0 | 0 12 0 0 0 1 0 0 | 0 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0
The first two bytes of each record is a selector to indicate what kind of path it is. 0 0 indicates that it is a Closed subpath length record.
The next 8 Bytes tell us the control point for the Bezier segment preceding the knot. Now this can again be split into two components X and Y
the first 4 bytes are the vertical components.
0 12 0 0
I converted 12 0 0 to binary format and add them and them convert to decimal
00001100 + 00000000 + 00000000 = 00001100
and then converted the result back to decimal. Which gave me Y co-ordinate.
where 0 indicates that the position is in the positive range(Signed magnitude form).
The next 8 bytes indicate the the anchor point for the knot, and the last 8 bytes the control point for the Bezier segment leaving the knot. The X and Y Components can be found in a similar manner.
I had this data exported to a svg file and then ran a rasterizer to convert the point data to pixel data.
If someone comes across this post I Hope this helps. :)

I'm new to visual basic and trying to understand how to set individual bits in a byte [closed]

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.
Closed 10 years ago.
Hi, I am new to Visual Basic, I have a project where I need to be able to manipulate individual bits in a value.
I need to be able to switch these bits between 1 and 0 and combine multiple occurrences of bits into one variable in my code.
Each bit will represent a single TRUE / FALSE value, so I'm not looking for how to do a single TRUE / FALSE value in one variable, but rather multiple TRUE / FALSE values in one variable.
Can someone please explain to me how I can achieve this please.
Many thanks in advance.
Does it have to be exactly one bit?
Why don't you just use the actual built in VB data type of Boolean for this.
http://msdn.microsoft.com/en-us/library/wts33hb3(v=vs.80).aspx
It's sole reason for existence is so you can define variables that have 2 states, true or false.
Dim myVar As Boolean
myVar = True
myVar = Flase
if myVar = False Then
myVar = True
End If
UPDATE (1)
After reading through the various answers and comments from the OP I now understand what it is the OP is trying to achieve.
As others have said the smallest unit one can use in any of these languages is an 8 bit byte. There is simply no order of data type with a smaller bit size than this.
However, with a bit of creative thinking and a smattering of binary operations, you can refer to the contents of that byte as individual bits.
First however you need to understand the binary number system:
ALL numbers in binary are to the power of two, from right to left.
Each column is the double of it's predecessor, so:
1 becomes 2, 2 becomes 4, 4 becomes 8 and so on
looking at this purely in a binary number your columns would be labelled thus:
128 64 32 16 8 4 2 1 (Remember it's right to left)
this gives us the following:
The bit at position 1 = 1;
The bit at position 2 = 2;
The bit at position 3 = 4;
The bit at position 4 = 8;
and so on.
Using this method on the smallest data type you have (The byte) you can pack 8 bit's into one value. That is you could use one variable to hold 8 separate values of 1 or 0
So while you cannot go any smaller than a byte, you can still reduce memory consumption by packing 8 values into 1 variable.
How do you read and write the values?
Remember the column positions? well you can use something called Bit Shifting and Bit masks.
Bit Shifting is the process of using the
<<
and
>>
operators
A shifting operation takes as a parameter the number of columns to shift.
EG:
Dim byte myByte
myByte = 1 << 4
In this case the variable 'myByte' would become equal to 16, but you would have actually set bit position 5 to a 1, if we illustrate this, it will make better sense:
mybyte = 0 = 00000000 = 0
mybyte = 1 = 00000001 = 1
mybyte = 2 = 00000010 = (1 << 1)
mybyte = 4 = 00000100 = (1 << 2)
mybyte = 8 = 00001000 = (1 << 3)
mybyte = 16 = 00010000 = (1 << 4)
the 0 through to 16 if you note is equal to the right to left column values I mentioned above.
given what Iv'e just explained then, if you wanted to set bits 5, 4 and 1 to be equal to 1 and the rest to be 0, you could simply use:
mybyte = 25(16 + 8 + 1) = 00011001 = (1 << 4) + (1 << 3) + 1
to get your bits back out, into a singleton you just bit shift the other way
retrieved bit = mybyte >> 4 = 00000001
Now there is unfortunately however one small flaw with the bit shifting method.
by shifting back and forth you are highly likely to LOOSE information from any bits you might already have set, in order to prevent this from happening, it's better to combine your bit shifting operations with bit masks and boolean operations such as 'AND' & 'OR'
To understand what these do you first need to understand simple logic principles as follows:
AND
Output is one if both the A and B inputs are 1
Illustrating this graphically
A B | Output
-------------
0 0 | 0
0 1 | 0
1 0 | 0
1 1 | 1
As you can see if a bit position in our input number is a 1 and the same position in our input number B is 1, then we will keep that position in our output number, otherwise we will discard the bit and set it to a 0, take the following example:
00011001 = Bits 5,4 and 1 are set
00010000 = Our mask ONLY has bit 5 set
if we perform
00011001 AND 0010000
we will get a result of
00010000
which we can then shift down by 5
00010000 >> 5 = 00000001 = 1
so by using AND we now have a way of checking an individual bit in our byte for a value of 1:
if ((mybyte AND 16) >> 1) = 1 then
'Bit one is set
else
'Bit one is NOT set
end if
by using different masks, with the different values of 2 in the right to left columns as shown previously, we can easily extract different singular values from our byte and treat them as a simple bit value.
Setting a byte is just as easy, except you perform the operation the opposite way using an 'OR'
OR
Output is one if either the A or B inputs are 1
Illustrating this graphically
A B | Output
-------------
0 0 | 0
0 1 | 1
1 0 | 1
1 1 | 1
eg:
00011001 OR 00000100 = 00011101
as you can see the bit at position 4 has been set.
To answer the fundamental question that started all this off however, you cannot use a data type in VB that has any resolution less than 1 byte, I suspect if you need absolute bit wise accuracy I'm guessing you must be writing either a compression algorithm or some kind of encryption system. :-)
01010100 01110010 01110101 01100101, is the string value of the word "TRUE"
What you want is to store the information in a boolean
Dim v As Boolean
v = True
v = False
or
If number = 84 Then ' 84 = 01010100 = T
v = True
End If
Other info
Technicaly you can't store anything in a bit, the smallest value is a char which is 8 bit. You'll need to learn how to do bitwise operation. Or use the BitArray class.
VB.NET (nor any other .NET language that I know of) has a "bit" data type. The smallest that you can use is a Byte. (Not a Char, they are two-bytes in size). So while you can read and convert a byte of value 84 into a byte with value 1 for true, and convert a byte of value 101 into a byte of value 0 for false, you are not saving any memory.
Now, if you have a small and fixed number of these flags, you CAN store several of them in one of the integer data types (in .NET the largest integer data type is 64 bits). Or if you have a large number of these flags you can use the BitArray class (which uses the same technique but backs it with an array so storage capacity is greater).