Re: [sqlite] Ideal way to check whether a table has a specific column

[David Bicking]

You could try to prepare a statement like "SELECT YourColumnName FROM 
YourTable;" If prepare returns an error, then likely the error message will say 
the column doesn't exist. If no error, it does exist. Such a simple query 
shouldn't take long to prepare. Probably less time then to grab the results of 
the pragma and test the strings therein.

David

--- On Tue, 11/3/09, Shaun Seckman (Firaxis)  wrote:

> From: Shaun Seckman (Firaxis) 
> Subject: [sqlite] Ideal way to check whether a table has a specific column
> To: "General Discussion of SQLite Database" 
> Date: Tuesday, November 3, 2009, 4:25 PM
> Hello all,
> 
>                 I
> just wanted to find out whether or not this is the
> most ideal method for determining if a column exists in a
> table.  My
> current technique is to do execute "pragma
> table_info(tableName)" then
> step through the results and perform a string comparison
> against the
> "name" column until I hit a match or I've finished stepping
> through the
> record set. 
> 
>  
> 
> Is there a better way?
> 
>  
> 
> Shaun Seckman
> 
> Firaxis Games
> Programmer
> 
>  
> 
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[sqlite] Ideal way to check whether a table has a specific column

[Shaun Seckman (Firaxis)]

Hello all,

I just wanted to find out whether or not this is the
most ideal method for determining if a column exists in a table.  My
current technique is to do execute "pragma table_info(tableName)" then
step through the results and perform a string comparison against the
"name" column until I hit a match or I've finished stepping through the
record set. 

 

Is there a better way?

 

Shaun Seckman

Firaxis Games
Programmer

 

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Re: [sqlite] Ideal way to check whether a table has a specific column

[Adam DeVita]

Another way

SELECT name, sql FROM sqlite_master WHERE type='table' and name ='yourtable
name'

the field sql will give you the full table structure as a string.  Parse for
your desired table name.

No statements fail.




On Tue, Nov 3, 2009 at 4:37 PM, Igor Tandetnik  wrote:

> Shaun Seckman (Firaxis)
>  wrote:
> >I just wanted to find out whether or not this is the
> > most ideal method for determining if a column exists in a table.  My
> > current technique is to do execute "pragma table_info(tableName)" then
> > step through the results and perform a string comparison against the
> > "name" column until I hit a match or I've finished stepping through
> > the record set.
> >
> > Is there a better way?
>
> I guess you could just prepare a statement "select mycolumn from mytable;"
> (you don't need to actually run it). If the column doesn't exist, prepare
> will fail.
>
> Igor Tandetnik
>
>
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> sqlite-users@sqlite.org
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Re: [sqlite] Ideal way to check whether a table has a specific column

[Igor Tandetnik]

Shaun Seckman (Firaxis)
 wrote: 
>I just wanted to find out whether or not this is the
> most ideal method for determining if a column exists in a table.  My
> current technique is to do execute "pragma table_info(tableName)" then
> step through the results and perform a string comparison against the
> "name" column until I hit a match or I've finished stepping through
> the record set.
> 
> Is there a better way?

I guess you could just prepare a statement "select mycolumn from mytable;" (you 
don't need to actually run it). If the column doesn't exist, prepare will fail.

Igor Tandetnik


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