Powershell Replace fail after test for null - powershell

I'm pulling data from a database (access specifically using ADO). Then I am preparing the variable for possible insertion into SQL later by replacing any existing single quotes with two single quotes.
Because the value coming from the database is very likely to be null, I test for it and the replace is only supposed to happen if it is NOT null. The value I'm getting it not registering as null when I test it, but when I try the replace, I get the error
Method invocation failed because [System.DBNull] does not contain a method named 'Replace'.
Here's the section of code $OldAbstract = $rs.Fields.Item("MetaAbstract").value
if($OldAbstract -ne $null) {$OldAbstract = $OldAbstract.Replace("'","''")}
After pulling the value, I print it and it looks like nothing. I tested it for null, and it says it's not. I tested it for "" and it's not. I even checked to see if it was a space, and it's not. The length is reported as 1... I'm at a loss as to what's going on.

You're testing for the wrong type of null - PowerShell/.net null instead of a database null. Try this (untested):
$OldAbstract = $rs.Fields.Item("MetaAbstract").value
if($OldAbstract -isnot [System.DBNull]) {$OldAbstract = $OldAbstract.Replace("'","''")}

Related

Why single quote escape cannot be used in QuestDB, Error: dangling expression

I'm trying to use Query Variables in Grafana, the panel query source is PostgreSQL for QuestDB.
I have added the variable without any issue, but I'm unable to use the variable in Panel query since the variable values contains the spaces (SENSOR01 ON_OFF), also I'm unable to figure-out how to add single quote escape.
Following are the scenarios I tried:
Scenario1: this indicates due to space in the Variable value, on_off considered as separate word
where sensor_name = $sensor
db query error: pq: unexpected token: on_off
.
.
Scenario2: tried to add single quotes explicitly for the variable value, but there is generic error from source DB (QuestDB)
where sensor_name = concat('''', $sensor, '''')
db query error: pq: dangling expression
When tried Scenario2 approach directly in query of Variable, getting the same error
..
Scenario3: Hard-coded the variable value with space and with single quotes, but this giving me error with first part of the variable, looks like the hard-coded single quotes not passed here!
Error (Scenario3):
Is there any way/workaround to tackle this issue?
Could you just add the quotes directly in the query?
where sensor_name = '$sensor'
I have a similar grafana panel querying a questDB database using a variable and it works for me. This is my query:
select device_type, avg(duration_ms) as avg_duration_ms, avg(speed) as avg_speed, avg(measure1) as avg_m1, avg(measure2) as avg_m2 from ilp_test
WHERE
$__timeFilter(timestamp) and device_type = '$deviceType'
A rather hacky workaround would be to do:
where sensor_name = concat(cast(cast('&' as int) + 1 as char), $sensor, cast(cast('&' as int) + 1 as char))
This should work, but I'm pretty sure there is a better solution. Let me find it and get back to you.
Update. We may support Postgres syntax (which is '' escaping for a single quote char) in one of upcoming versions. For now, you'd have to use the above workaround.

Add a missing key to JSON in a Postgres table via Rails

I'm trying to use update_all to update any records that is missing a key in a JSON stored in a table cell. ids is the ids of those records and I've tried the below...
User.where(id: ids).
update_all(
"preferences = jsonb_set(preferences, '{some_key}', 'true'"
)
Where the error returns is...
Caused by PG::SyntaxError: ERROR: syntax error at or near "WHERE"
LINE 1: ...onb_set(preferences, '{some_key}', 'true' WHERE "user...
The key takes a string value so not sure why the query is failing.
UPDATE:
Based on what was mentioned, I added the parentheses and also added / modified the last two arguments...
User.where(id: ids).
update_all(
"preferences = jsonb_set(preferences, '{some_key}', 'true'::jsonb, true)"
)
still running into issues and this time it seems related to the key I'm passing
I know this key doesn't currently exist for the set of ids
I added true for create_missing so that 1 isn't an issue
I get this error now...
Caused by PG::UndefinedFunction: ERROR: function jsonb_set(hstore, unknown, jsonb, boolean) does not exis
some_key should be a key in preferences
You're passing in raw SQL so you are 100% responsible for ensuring that is actually valid SQL. What you have there isn't. Check your parentheses:
User.where(id: ids).
update_all(
"preferences = jsonb_set(preferences, '{some_key}', 'true')"
)
If you look more closely at the error message it was telling you there was a problem precisely at the introduction of the WHERE clause, and right after ...true' so that was a good place to look for problems.
Syntax errors like this can be really annoying, but don't forget your database will usually do its best to pin down the place where the problem occurs.

Powershell Parameter passing issue

I have a strange one I have searched the existing Q&A and haven't found a match.
I have written my functions using parameter validation using the basic format
function FunctioName
{
[CmdletBinding()]
Param(
[parameter(Mandatory)]
[String]$VariableName
)
When I set the parameter to Mandatory as above I get a parameter binding exception indicating a null value was passed. Running the script in debug I can see the function parameter being passed is not null and is a valid string.
When I run the script in the exact same way without the mandatory flag the string is passed into the function and it executes correctly.
Has anyone got any ideas, what could be the issue. This problem is affecting a number of functions in my application interestingly it appears that the affected functions all have only a single parameter functions with multiple parameters do not appear to be affected.
Ok thanks guys for your feedback its much appreciated. BTW i am using powershell 5 .
Further to the issue, looking into it further I found that the variable was being passed to the function as an array of strings, however an empty string value was being appended into the array which I believe was the cause for the issue. This is where it starts to get interesting, I will need to give a bit more background.
The script I am running queries active directory for user attributes meeting specific conditions, those that match I create an array of strings with each value a delimited value of the user,hostname and other attribute properties.
To ensure that I am getting the latest values I use the ASDI GetInfo method,which seems to trigger the odd behavior.
At a high level the functions are
Function GetuserAttr
{
$inscopeusers = New-Object System.Collections.ArrayList
$accountlist = (Get-ADUser -Filter { attribute1 -eq "value"} -Properties attribute1).SamAccountName
foreach ($user in $accountlist)
{
$DN = getDN($user) # basically a funtion I wrote to create ASDI object for user account.
$DN.GetInfo() # this method call appears to cause issues
$attr1 = $DN.Get("Attribute1")
$attr2 = $DN.Get("Attribute2")
$hoststring = "$($user)|$($attr1)|$($attr2)"
$inscopeusers.Add($hoststring) > null
}
return $inscopeusers
}
The string array returned in this function is fed into a number of other functions, one of which is the one that was giving the error that I originally brought up.
The thing is when I use the GetInfo method the array returned by this function contains several null values in the array, when I remove the command the array has no null strings.
Even more strange when I am operating on the array in other functions it appears that the array looses some of its properties when the GetInfo method is used. So for instance I am able to use the foreach loop to iterate through array values but I cannot access an array value by index such as $array[1].
By simply commenting out the GetInfo method call in the function the array returned seems to function normally and you can access array values by index.
I have another function that also uses GetInfo and returns a hash table, when I try to operate on the returned hashtable I cannot access values using a key value such as $hashtable['key'], but I can access them using $hashtable.key. I know this is really weird and can't really think what it could be
Has any one else experienced a similar problem.
You're missing an argument.
Function Test
{
[CmdletBinding()]
Param(
[Parameter(Mandatory=$True)]
[String]
$Variable
)
Write "$Variable"
}

Why output value is cut when adParamInputOutput is used?

I have stored procedure which has VARCHAR(MAX) OUTPUT parameter. The parameter is used to both pass and return large string value.
It is working perfectly when it is executed in the context of the SQL Server Management Studio.
The issue appears only in the ASP page. Here is the code:
cmd.Parameters.Append cmd.CreateParameter("#CSV", adBStr, adParamInputOutput, -1, 'some very large string goes here')
I am able to pass a large value (more then 4000 symbols) but the return value is cut. I have try to replace the adBStr with adLongVarWChar and adLongVarChar but I get the following error:
Parameter object is improperly defined. Inconsistent or incomplete
information was provided.
I guess the problem is caused by the adParamInputOutput. So, I am generally asking for a parameter type that will work in both direction with maximum symbols.

Empty parameter in Crystal Reports Not showing NULL

I have a parameter that prompts the user to enter a value.
If that field is left blank I would think that the parameter would be NULL.
If I run:
isnull({?Param}) then
run this code...
The code does not run
BUT if I run it like:
hasvalue({?Param})
run this code...
The code runs!
Any idea why an empty param field does not return NULL?
From what I know,
hasvalue is used to check if a parameter has a value specified whereas IsNULL is mainly used in conjunction with a database field.
Which is why it may be behaving like that in your case.