In an XmlData column in SQL Server 2008 that has no schema assigned to it, how can I pull the first item at a particular node level? For example, I have:
SELECT
XmlData.value('//*/*[1]','NVARCHAR(6)')
FROM table
where XmlData.Exist('//*/*[1]') = 1
I assume this does not work because if there are multiple nodes with different names at the 2nd level, the first of each of those could be returned (and the value() requires that a singleton be selected.
Since I don't know what the names of any nodes will be, is there a way to always select whatever the first node is at the 2nd level?
I found the answer by chaining Xquery .query() and .value()
XMLDATA.query('//*/*[1]').value('.[1]','NVARCHAR(6)')
This returns the value of the first node and works perfectly for my needs.
Related
I am trying to create a custom template fragment that builds a table of value properties. I started by creating a SQL query fragment that pulls all properties classified by a Value Type. Now I would like to pull in the default (initial) value assigned. I figured out that it's in the Description table of t_xref, with the property guid in the client field, but I don't know how to write a query that will reliably parse the default value out since the string length may be different depending on other values set. I tried using the template content selector first but I couldn't figure out how to filter to only value properties. I'm still using the default .qeax file but will be migrating to a windows based DBMS soon. Appreciate any help!
Tried using the content selector. Successfully built a query to get value properties but got stuck trying to join and query t_xref for default value.
Edited to add current query and image
Value Properties are block properties that are typed to Value Types. I'm using SysML.
This is my current query, I am no SQL expert! I don't pull anything from t_xref yet but am pulling out only the value properties with this query:
SELECT property.ea_guid AS CLASSGUID, property.Object_Type AS CLASSTYPE, property.Name, property.Note as [Notes], classifier.Name AS TYPE
FROM t_object property
LEFT JOIN t_object classifier ON property.PDATA1 = classifier.ea_guid
LEFT JOIN t_object block on property.ParentID = block.Object_ID
WHERE block.Object_ID = #OBJECTID# AND property.Object_Type = 'Part' AND classifier.Object_Type = 'DataType'
ORDER BY property.Name
I guess that Geert will come up with a more elaborate answer, but (assuming you are after the Run State) here are some details. The value for these Run States is stored in t_object.runstate as one of the crude Sparxian formats. You find something like
#VAR;Variable=v1;Value=4711;Op==;#ENDVAR;
where v1 is the name and 4711 the default in this example. How you can marry that with your template? Not the faintest idea :-/
I can't give a full answer to the original question as I can't reproduce your data, but I can provide an answer for the generic problem of "how to extract data through SQL from the name-value pair in t_xref".
Note, this is heavily dependent on the database used. The example below extracts fully qualified stereotype names from t_xref in SQL Server for custom profiles.
select
substring(
t_xref.Description, charindex('FQName=',t_xref.Description)+7,
charindex(';ENDSTEREO',t_xref.Description,charindex('FQName=',t_xref.Description))
-charindex('FQName=',t_xref.Description)-7
),
Description from t_xref where t_xref.Description like '%FQName%'
This works using:
substring(string, start, length)
The string is the xref description column, and the start and length are set using:
charindex(substring, string, [start position])
This finds the start and end tags within the xref description field, for the data you're trying to parse.
For your data, I imagine something like the below is the equivalent (I haven't tested this). It's then a case of combining it with the query you've already got.
select
substring(
t_xref.Description, #the string to search in
charindex('#VALU=',t_xref.Description,charindex('#NAME=default',t_xref.Description)+6, #the start position, find the position of the first #VALU= tag after name=default
charindex('#ENDVALU;',t_xref.Description,charindex('#VALU=',t_xref.Description))
-charindex('#VALU=',t_xref.Description,charindex('#NAME=default',t_xref.Description))-6 #the length, find the position of the first #ENDVALU tag after the start, and subtract it from the start position
),
Description from t_xref where t_xref.Description like '%#NAME=default%' #filter anything which doesn't contain this tag to avoid "out of range" index errors
First off this is my first attempt at a multi select. I've done a lot of searching but I can't find the answer that works for me.
I have a postgresql query which has bg.revision_key in (_revision_key) which holds the parameter. A side note, we've named all our parameters in the queries with the underscore and they all work, they are single select in SSRS.
In my SSRS report I have a parameter called Revision Key Segment which is the multi select parameter. I've ticked Allow multi value and in Available Values I have value field pointing to revision_key in the dataset.
In my dataset parameter options I have Parameter Value [#revision_key]
In my shared dataset I also have my parameter set to Allow multi value.
For some reason I can't seem to get the multi select to work so I must be missing something somewhere but I've ran out of ideas.
Unlike with SQL Server, when you connect to a database using an ODBC connection, the parameter support is different. You cannot use named parameters and instead have to use the ? syntax.
In order to accommodate multiple values you can concatenate them into a single string and use a like statement to search them. However, this is inefficient. Another approach is to use a function to split the values into an in-line table.
In PostgreSQL you can use an expression like this:
inner join (select CAST(regexp_split_to_table(?, ',') AS int) as filter) as my on my.filter = key_column
Then in the dataset properties, under the parameters tab, use an expression like this to concatenate the values:
=Join(Parameters!Keys.Value, ",")
In other words, the report is concatenating the values into a comma-separated list. The database is splitting them into a table of integers then inner joining on the values.
I am trying to pull data from DB2 via informatica, I have a SQ query that pulls few fields based on joins for 4 different tables.
When I run the query directly in the database, it returns the expected result, however when I run it in informatica and run a debugger, I see something else.
Please note all the columns data perfectly match, except one single column.
Weird thing is, this is a calculated field from the table based on a case statement:
CASE WHEN Column1='3' THEN 'N' ELSE 'Y' END.
Since this is a calculated field with a length of one string, I have connected from the source to SQ from one of the sources having 1 character length.
This returns 'Y' when executed in the database, the same query when I copy paste in SQ of information and run it, I get a data 'E', and this data can never be possible as I expect only a N or a Y. I have verified the column order, that its in the right place. This is very strange, is something going wrong because of the CASE Statement?
Save yourself the hassle, put an expression transformation after tge source qualifier and calculate, port value there then forget about it
I think i got the issue. We use Informatica PowerExchange to connect to a as400 system(DB2), and it seems that when we are trying to set a flag information in AS400, and pass it to informatica via PowerExchange, it converts it to binary, and to solve this, there needs to be an entry in the PowerExchange configuration file.
Unfortunately, i myself was not aware that it could be related to PowerExchange instead of powercenter itself.!!
Thanks for your assistance! Below is the KB about it.
https://kb.informatica.com/solution/4/Pages/17498.aspx
I'm relatively new to DB2 for IBMi and am wondering the methods of how to properly cleanse data for a dynamically generated query in PHP.
For example if writing a PHP class which handles all database interactions one would have to pass table names and such, some of which cannot be passed in using db2_bind_param(). Does db2_prepare() cleanse the structured query on its own? Or is it possible a malformed query can be "executed" within a db2_prepare() call? I know there is db2_execute() but the db is doing something in db2_prepare() and I'm not sure what (just syntax validation?).
I know if the passed values are in no way effected by the result of user input there shouldn't be much of an issue, but if one wanted to cleanse data before using it in a query (without using db2_prepare()/db2_execute()) what is the checklist for db2? The only thing I can find is to escape single quotes by prefixing them with another single quote. Is that really all there is to watch out for?
There is no magic "cleansing" happening when you call db2_prepare() -- it will simply attempt to compile the string you pass as a single SQL statement. If it is not a valid DB2 SQL statement, the error will be returned. Same with db2_exec(), only it will do in one call what db2_prepare() and db2_execute() do separately.
EDIT (to address further questions from the OP).
Execution of every SQL statement has three stages:
Compilation (or preparation), when the statement is parsed, syntactically and semantically analyzed, the user's privileges are determined, and the statement execution plan is created.
Parameter binding -- an optional step that is only necessary when the statement contains parameter markers. At this stage each parameter data type is verified to match what the statement text expects based on the preparation.
Execution proper, when the query plan generated at step 1 is performed by the database engine, optionally using the parameter (variable) values provided at step 2. The statement results, if any, are then returned to the client.
db2_prepare(), db2_bind_param(), and db2_execute() correspond to steps 1, 2 and 3 respectively. db2_exec() combines steps 1 and 3, skipping step 2 and assuming the absence of parameter markers.
Now, speaking about parameter safety, the binding step ensures that the supplied parameter values correspond to the expected data type constraints. For example, in the query containing something like ...WHERE MyIntCol = ?, if I attempt to bind a character value to that parameter it will generate an error.
If instead I were to use db2_exec() and compose a statement like so:
$stmt = "SELECT * FROM MyTab WHERE MyIntCol=" . $parm
I could easily pass something like "0 or 1=1" as the value of $parm, which would produce a perfectly valid SQL statement that only then will be successfully parsed, prepared and executed by db2_exec().
I have a node with id 1 and a node with id 2 in the database and they are linked to each other. Why when I run this query
MATCH (a)-[r]-(b) WHERE id(a)=1 AND id(b)=2 RETURN *;
Nothing is returned?
Solution
I use GrapheneDB. Usually GrapheneDB presents the system node id on the node graphic but when you have an attribute id it presents that instead. When I ran the query I was using the graphic id which wasn't actually the system id so id(a) didn't give the expected result.
Because the WHERE clause is evaluated for each candidate result, and the entire clause must evaluate to true.
Also, putting MATCH (a)-[r]-(b) will only find parts of the graph where those two nodes are related.
If you just want to find nodes 1 and 2, you can do this:
MATCH n
WHERE id(n) = 1 OR id(n) = 2
RETURN n
However, you should not be using node ids. They are deprecated, and being phased out. There are lots of other ways to find and identify nodes that don't rely on their internal identifier. If you open a new question with your actual scenario, we could help you write a better query.