Re: [pgadmin-hackers] [pgAdmin4][Patch]: Fix RM1790 - [Web] Supportsetting a field's value to "null" - Mailing list pgadmin-hackers

Hi

On Fri, Jan 13, 2017 at 9:24 AM, Surinder Kumar
<surinder.kumar@enterprisedb.com> wrote:
> Hi
>
> Please find attached patch and review.
>
> On Sun, Jan 8, 2017 at 3:27 PM, Dave Page <dpage@pgadmin.org> wrote:
>>
>> Hi
>>
>> On Friday, December 23, 2016, Surinder Kumar
>> <surinder.kumar@enterprisedb.com> wrote:
>>>
>>> Forgot to attach patch in last thread. please find patch.
>>
>>
>> It looks good for the most part, except:
>>
>> 1) You missed the part we discussed about being able to set a value to ''
>> (the literal string containing two single quotes) by entering \'\' (and of
>> course, the follow-on cases to allow setting a value to \'\' by entering
>> \\'\\' etc).
>
> Fixed.

That doesn't seem right to me - the code you've written looks like
it'll try to escape anything for use in a string literal, not just
'\'\ or \\'\\' etc.

>> 2) Could you please update the appropriate doc page to explain how this
>> all works? You can lift the text from the pgAdmin 3 docs for the most part.
>
> I will send a separate patch for it.
>>
>>
>> Thanks.
>>
>>>
>>>
>>> On Fri, Dec 23, 2016 at 11:24 AM, Surinder Kumar
>>> <surinder.kumar@enterprisedb.com> wrote:
>>>>
>>>> On Fri, Dec 23, 2016 at 11:11 AM, Surinder Kumar
>>>> <surinder.kumar@enterprisedb.com> wrote:
>>>>>
>>>>> Hi Dave,
>>>>>
>>>>> Please find updated patch.
>>>>>
>>>>> Changes implemented:
>>>>>
>>>>> 1) To enter an empty string in string/character type, user need to
>>>>> enter '' (two single quotes).
>>>>> 2) To enter null values in Integer/String type, user need to keep the
>>>>> field blank.
>>>>> 3) Null values will be represented as [null].
>>>>>
>>>>> Please find attached patch and review.
>>>>>
>>>>> On Fri, Dec 9, 2016 at 2:23 PM, Surinder Kumar
>>>>> <surinder.kumar@enterprisedb.com> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Dec 5, 2016 at 11:09 PM, Dave Page <dpage@pgadmin.org> wrote:
>>>>>>>
>>>>>>> Hi
>>>>>>>
>>>>>>> On Friday, December 2, 2016, Surinder Kumar
>>>>>>> <surinder.kumar@enterprisedb.com> wrote:
>>>>>>>>
>>>>>>>> Hi
>>>>>>>>
>>>>>>>> Issue:
>>>>>>>> - On viewing table data, If we edit a column and set value of
>>>>>>>> column(type: text) to "null", It always takes it as empty string. It doesn't
>>>>>>>> honour null values.
>>>>>>>>
>>>>>>>> Solution:
>>>>>>>> - Take a flag "is_null" for columns with data type 'text', then on
>>>>>>>> GUI, whilst user edits a text field, an additional option with
>>>>>>>> checkbox(is_null ?) is given to take null values. If checkbox is checked, on
>>>>>>>> JS side we check "is_null" flag and pass field value to null if selected.
>>>>>>>>
>>>>>>>> Please find patch and review.
>>>>>>>
>>>>>>>
>>>>>>> A nice solution, but there are some problems I think;
>>>>>>>
>>>>>>> - How do I set a field that doesn't use the text editor to null? e.g.
>>>>>>> an integer? If I try to set one to blank, I get an error that it's invalid
>>>>>>> input syntax for an integer.
>>>>>>
>>>>>> It seems possible by writing custom editor which will convert empty
>>>>>> string to null before save operation.
>>>>>
>>>>> Now If you set blank for integer field, field will set to null.
>>>>>>>
>>>>>>>
>>>>>>> - When null values are first displayed, they are shown as blank
>>>>>>> entries. If I then set one to null, it displays "null". It should always
>>>>>>> display consistently - I'd suggest "[null]"
>>>>>>
>>>>>> Ok. But the issue is if we display "[null]" in cell for null entry.
>>>>>> How would we distinguish If it is user entered string(as user can also enter
>>>>>> "[null]") or it represent null value ? (Ashesh's concern)
>>>>>
>>>>> Now null values will be represented in field as [null].
>>>>>>>
>>>>>>>
>>>>>>> Whilst I like the way this works in part, I think it's going to be
>>>>>>> inconsistent in the way it would be displayed. I think we need to follow the
>>>>>>> pgAdmin III way of handling this. The docs say the following:
>>>>>>>
>>>>>>> ====
>>>>>>> If an SQL NULL is to be written to the table, simply leave the field
>>>>>>> empty. If you store a new row, this will let the server fill in the default
>>>>>>> value for that column. If you store a change to an existing row, the value
>>>>>>> NULL will explicitly be written.
>>>>>>>
>>>>>>>
>>>>>>> ...
>>>>>>>
>>>>>>> If you want pgAdmin III to write an empty string to the table, you
>>>>>>> enter the special string ‘’ (two single quotes) in the field. If you want to
>>>>>>> write a string containing solely two single quotes to the table, you need to
>>>>>>> escape these quotes, by typing \‘\’
>>>>>
>>>>> To write an empty string, now user can enter '' (two single quotes), it
>>>>> will be treated as empty string.
>>>>>>>
>>>>>>> ====
>>>>>>>
>>>>>>> In other words, if an empty value is included for a new row, that
>>>>>>> column will be omitted from the INSERT statement, allowing the server to use
>>>>>>> a default, or set it to blank.
>>>>>>>
>>>>>>> For existing rows, an empty value for any data type is updated as
>>>>>>> NULL - e.g. col = NULL.
>>>>>>>
>>>>>>> For character/string types, if the user enters '', then an empty
>>>>>>> string is written to the column when either inserting or updating.
>>>>>>>
>>>>>>>
>>>>>>> If the user wishes to insert the literal string '' (i.e. 2 single
>>>>>>> quotes), then \'\' must be entered, and pgAdmin converts that to ''.
>>>>>>>
>>>>>>>
>>>>>>> To enter a literal string of \'\', then the user enters \\'\\', for
>>>>>>> \\'\\' they enter \\\\'\\\\' and so on.
>>>>>
>>>>> If a user enters a literal string \'\', this value is escaped by adding
>>>>> slashes on python side and unescaped by removing added slashes when returned
>>>>> to display.
>>>>> the entered values are already escaped, user need not to escape values.
>>>>>>
>>>>>> This behaviour seems to working wine in pgAdmin3 query tool but not on
>>>>>> viewing data by right click context menu.
>>>>>>
>>>>>>
>>>>>> In view data:
>>>>>> When user enter literal strings like '', \'\'
>>>>>> &
>>>>>> \\'\\', it displays these strings as it is after saving. It seems
>>>>>> conversion doesn't happen.
>>>>>> so which one is correct to follow in pgAdmin4?
>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Thanks.
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Dave Page
>>>>>>> Blog: http://pgsnake.blogspot.com
>>>>>>> Twitter: @pgsnake
>>>>>>>
>>>>>>> EnterpriseDB UK: http://www.enterprisedb.com
>>>>>>> The Enterprise PostgreSQL Company
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>>
>> --
>> Dave Page
>> Blog: http://pgsnake.blogspot.com
>> Twitter: @pgsnake
>>
>> EnterpriseDB UK: http://www.enterprisedb.com
>> The Enterprise PostgreSQL Company
>>
>



--
Dave Page
Blog: http://pgsnake.blogspot.com
Twitter: @pgsnake

EnterpriseDB UK: http://www.enterprisedb.com
The Enterprise PostgreSQL Company