Re: [sqlite] C# Dynamic data type
Interesting idea. Thanks.
Adam
On Tue, Aug 7, 2012 at 12:07 PM, Black, Michael (IS)
michael.bla...@ngc.com wrote:
You can use sscanf to determine data type...I've done it before using a
method that's not obvious...
You parse from most restrictive to least restrictive format like this...this
will accept any valid float format including scientific notation.
#include stdio.h
enum {UNKNOWN, FLOAT, INT, STRING};
int datatype(char *s)
{
long i;
double f;
char buf[4096];
int n;
n = sscanf(s,%d%s,i,buf);
if (n == 1) {
printf(INT\n);
return INT;
}
n = sscanf(s,%lg%s,f,buf);
if (n == 1) {
printf(FLOAT\n);
return FLOAT;
}
n = sscanf(s,%s,buf);
if (n == 1) {
printf(STRING\n);
return STRING;
}
else {
printf(UNKNOWN\n);
return UNKNOWN; // should never get here
}
}
main()
{
char *line1=1234;
char *line2=1234.5;
char *line3=x1234.5;
datatype(line1);
datatype(line2);
datatype(line3);
}
~
Michael D. Black
Senior Scientist
Advanced Analytics Directorate
Advanced GEOINT Solutions Operating Unit
Northrop Grumman Information Systems
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Adam DeVita [adev...@verifeye.com]
Sent: Tuesday, August 07, 2012 10:26 AM
To: General Discussion of SQLite Database
Subject: EXT :[sqlite] C# Dynamic data type
Good day,
I've been reading a bit of conflicted stuff online in terms of data type.
The most basic question, in C#, is can you easily determine the data
type of the Nth entry in a column.
{Ex: Create table A( x TEXT, y )
... a few inserts, binding a float, then a string, then an int into y..
select x,y from A
check the type of y before retrieving a value from it.
}
The docs for SQLiteDataReader.GetFieldType() seems to read as if it
will return the column affinity.
regards,
Adam
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[sqlite] C# Dynamic data type
Good day,
I've been reading a bit of conflicted stuff online in terms of data type.
The most basic question, in C#, is can you easily determine the data
type of the Nth entry in a column.
{Ex: Create table A( x TEXT, y )
... a few inserts, binding a float, then a string, then an int into y..
select x,y from A
check the type of y before retrieving a value from it.
}
The docs for SQLiteDataReader.GetFieldType() seems to read as if it
will return the column affinity.
regards,
Adam
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
Re: [sqlite] C# Dynamic data type
You can use sscanf to determine data type...I've done it before using a method
that's not obvious...
You parse from most restrictive to least restrictive format like this...this
will accept any valid float format including scientific notation.
#include stdio.h
enum {UNKNOWN, FLOAT, INT, STRING};
int datatype(char *s)
{
long i;
double f;
char buf[4096];
int n;
n = sscanf(s,%d%s,i,buf);
if (n == 1) {
printf(INT\n);
return INT;
}
n = sscanf(s,%lg%s,f,buf);
if (n == 1) {
printf(FLOAT\n);
return FLOAT;
}
n = sscanf(s,%s,buf);
if (n == 1) {
printf(STRING\n);
return STRING;
}
else {
printf(UNKNOWN\n);
return UNKNOWN; // should never get here
}
}
main()
{
char *line1=1234;
char *line2=1234.5;
char *line3=x1234.5;
datatype(line1);
datatype(line2);
datatype(line3);
}
~
Michael D. Black
Senior Scientist
Advanced Analytics Directorate
Advanced GEOINT Solutions Operating Unit
Northrop Grumman Information Systems
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Adam DeVita [adev...@verifeye.com]
Sent: Tuesday, August 07, 2012 10:26 AM
To: General Discussion of SQLite Database
Subject: EXT :[sqlite] C# Dynamic data type
Good day,
I've been reading a bit of conflicted stuff online in terms of data type.
The most basic question, in C#, is can you easily determine the data
type of the Nth entry in a column.
{Ex: Create table A( x TEXT, y )
... a few inserts, binding a float, then a string, then an int into y..
select x,y from A
check the type of y before retrieving a value from it.
}
The docs for SQLiteDataReader.GetFieldType() seems to read as if it
will return the column affinity.
regards,
Adam
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
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sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
