this question is in relation to my previous question: Linq2Entity Getting Values from reference Table
Now i have the problem that i want to add a new entry in Table B. I tried something like this:
ObjectQuery<A> aTable = dbConnection.A;
ObjectQuery<B> bTable = dbConnection.B;
var data = from d in aTable //Reference dataset in Table A
where d.ID == myID
select d;
B bData = new B()
{
ID = GetNewID(),
Text = text,
A = data.First()
};
dbConnection.AddToB(bData);
but this "A = d.First()" does now work... Any ideas? Thx!
Related
Hi i am new to oracle_sqldeveloper can you please give me the answer how to know the table structure and relationships of a database.
You can try
DESC <table_name>
Try this:
select table_name, column_name, data_type
from all_tab_columns
where table_name = <TABLE_NAME_HERE>
and owner = '<YOUR_USER_HERE_IN_CAPITAL_LETTERS>'
If you have comments on your table then to get columns' comments:
select tc.table_name, tc.column_name, tc.data_type, cc.comments
from all_col_comments cc, all_tab_columns tc
where tc.table_name = <TABLE_NAME_HERE>
and tc.owner = <OWNER_OF_TABLE_HERE>
and tc.table_name = cc.table_name
and tc.column_name = cc.column_name
and tc.owner = cc.owner
If you are logged in under owner of the table you can write this:
select table_name, column_name, data_type
from user_tab_columns
where table_name = <TABLE_NAME_HERE>
or to get columns with comments
select tc.table_name, tc.column_name, tc.data_type, cc.comments
from user_col_comments cc, user_tab_columns tc
where tc.table_name = '<TABLE_NAME_HERE>'
and tc.owner = '<YOUR_USER_HERE_IN_CAPITAL_LETTERS>'
and tc.table_name = cc.table_name
and tc.column_name = cc.column_name
To get relationships between tables user this query:
select uc1.table_name
, uc1.constraint_name
, cc1.column_name
, uc2.table_name r_table_name
, uc2.constraint_name r_constraint_name
, cc2.column_name r_column_name
from all_constraints uc1
, all_constraints uc2
, all_cons_columns cc1
, all_cons_columns cc2
where 1 = 1
and uc2.constraint_type = 'R'
and uc1.constraint_name = uc2.r_constraint_name
and cc1.table_name = uc1.table_name
and cc1.constraint_name = uc1.constraint_name
and cc2.table_name = uc1.table_name
and cc2.constraint_name = uc1.constraint_name
and uc1.owner = '<YOUR_USER_HERE_IN_CAPITAL_LETTERS>'
and uc2.owner = uc1.owner
and cc1.owner = uc1.owner
and cc2.owner = uc1.owner
order by 1
/
Columns with the "R_" prefix mean that they are foreign data (they represent foreign keys). As you can see, I used the tables with the "ALL_" prefix, to use similar tables with the "USER_" prefix, get rid of the "OWNER" section.
To know more about oracle data dictionary read this
1) type your table name.
2) right click on table name & click Open Declaration.
Table1 :
userid name address
1 venkat srinagr
2 venkatesh sainagar
Table2:
id userid lat lon
1 1 14.000 15.000
2 2 14.3526 15.3698
by passing "venkat" as parameter then need to pull all matching records and his userid,name,lat,lon.
in above table1 "venkat" contains in both rows then need to pull 2 records.how to get userid,name,lat,lon for all matching rows..
for sigle record i am able to get.but there are multiple rows how to get please tell me....
var result = from p in cxt.Table2
where p.Table1.Name.Contains(name)
select new
{
p.Users.User_Id,p.Users.Name,p.Latitude,p.Longitude
};
Im sure someone will say this is not the most effective way but this is how i would do it.
string InputString = "venkat";
var tab =(from a in db.tablea
from b in db.tableb
where a.userid == b.userid && a.name == InputString
select new
{
UserID = a.userid,
Username = a.name,
Latitude = b.lat,
Longditude = b.lon
}).FirstOrDefault();
FirstOrDefault() is only if you want to force only one output or null,
if you want a collection of some sort, then just remove it.
I have read plenty of blog posts and have yet to find a clear and simple example of how to perform a LEFT OUTER JOIN between two tables. The Wikipedia article on joins Join (SQL) provides this simple model:
CREATE TABLE `employee` (
`LastName` varchar(25),
`DepartmentID` int(4),
UNIQUE KEY `LastName` (`LastName`)
);
CREATE TABLE `department` (
`DepartmentID` int(4),
`DepartmentName` varchar(25),
UNIQUE KEY `DepartmentID` (`DepartmentID`)
);
Assume we had a EmployeeSet as an employee container ObjectSet<Employee> EmployeeSet and a DepartmentSet ObjectSet<Department> DepartmentSet. How would you perform the following query using Linq?
SELECT LastName, DepartmentName
FROM employee e
LEFT JOIN department d
ON e.DepartmentID = d.DepartmentID
I would write this, which is far simpler than join and does exactly the same thing:
var q = from e in db.EmployeeSet
select new
{
LastName = e.LastName,
DepartmentName = e.Department.DepartmentName
};
You need to use the DefaultIfEmpty method :
var query =
from e in db.EmployeeSet
join d in db.DepartmentSet on e.DepartmentID equals d.DepartmentID into temp
from d in temp.DefaultIfEmpty()
select new { Employee = e, Department = d };
select ForumCategories.ID , ForumCategories.Title , ForumCategories.DateCreated,
CO = ( select COUNT(*) from ForumSubCategories where ForumSubCategories.CategoryID_FK = ForumCategories.ID)
from ForumCategories
var q = from fc in Context.ForumCategories
select new
{
Id = fc.ID,
Title = fc.Title,
DateCreated = fc.DateCreated
CO = fc.ForumSubCategories.Count()
};
return q;
The "join" (subquery) is implicit; it's defined in the relationship between ForumCategories and ForumSubCategories in your model. Using this syntax, the call to Count() will be done on the DB server.
Im using query in crystal report like:
if({?User Name}) <>"ALL"
then
{COMN_USER_RESP_LINK_T.APPL_USER_NAME}={?User Name}
else
{COMN_USER_RESP_LINK_T.APPL_USER_NAME} ={COMN_USER_RESP_LINK_T.APPL_USER_NAME}
and
{COMN_USER_RESP_LINK_T.ENABLED}="Y"
this is actual query in sql:
SELECT
C.APPL_USER_NAME,
A.RESP_NAME,
B.MENU_NAME,
B.DESCRIPTION,
B.MODULE_NAME,
C.APPL_RESP
FROM COMN_RESPONSIBILITY_T A,
COMN_RESP_MENU_LINK_T B,
COMN_USER_RESP_LINK_T C
WHERE A.COMP_CODE = B.COMP_CODE
AND B.COMP_CODE = C.COMP_CODE
AND C.COMP_CODE = A.COMP_CODE
AND A.RESP_NAME = B.RESP
AND C.APPL_RESP = A.RESP_NAME
AND B.ENABLED = 'Y'
AND C.APPL_USER_NAME = c.APPL_USER_NAME
CASE #ACCT_CODE_FROM
WHEN 'ALL' THEN C.APPL_USER_NAME
ELSE #ACCT_CODE_FROM
END
ORDER BY APPL_USER_NAME,
RESP_NAME
I should select user name in parameter field(?user name), if I select ALL then I have to show all records ({COMN_USER_RESP_LINK_T.APPL_USER_NAME})
is the above query correct?
I would probably rephrase that as something like:
SELECT C.APPL_USER_NAME, A.RESP_NAME, B.MENU_NAME, B.DESCRIPTION,
B.MODULE_NAME, C.APPL_RESP
FROM COMN_RESPONSIBILITY_T A
INNER JOIN COMN_RESP_MENU_LINK_T B ON A.COMP_CODE = B.COMP_CODE
AND A.RESP_NAME = B.RESP
INNER JOIN COMN_USER_RESP_LINK_T C ON B.COMP_CODE = C.COMP_CODE
AND C.APPL_RESP = A.RESP_NAME
WHERE ((#ACCT_CODE_FROM = 'ALL') AND (B.ENABLED = 'Y'))
OR (C.APPL_USER_NAME = #ACCT_CODE_FROM)
ORDER BY APPL_USER_NAME, RESP_NAME
This gets you the details for either:
when ALL is selected, all accounts that are enabled; or
just the user code entered
i don't read your code because it is very dirty! but i think you can use SelectionFormula in crystal report. Certainly you can set it in code :
crystalReportViewer1.SelectionFormula ="(({?User Name}= 'ALL') AND ({B.ENABLED} = 'Y'))
OR ({C.APPL_USER_NAME} = #ACCT_CODE_FROM)"