I am using a stored procedure to fill a DataSet. What I need to do is force the name of the DataTable that is created when filled. There are multiple tables returned from the Stored Procedure. The last table is the one I need to make sure has a specific name when returned. It is created by returning a value of a variable and not pulling from any tables.
SELECT #Phone as My_800Number
How can I make this return as table called "D1Header"?
There is no ADO.NET Native way to do it; ADO.Net assign a generated name with a sequence number, according to this
You can workaround it... if you say you need the last table with a specific name, you can do:
if (ds.Tables.Count > 0) {
ds.Tables[ds.Tables.Count - 1].TableName = "name";
}
Could use an enum of the table names and reference that in your table reference rather than the table itself.
ds.tables(myEnum.Contacts).rows ?
Related
I have I table consisting of 3 columns: system, module and block. Table is filled in a procedure which accepts system, module and block and then it checks if the trio is in the table:
select count(*) into any_rows_found from logs_table llt
where system=llt.system and module=llt.module and block=llt.block;
If the table already has a row containing those three values, then don't write them into the table and if it doesn't have them, write them in. The problem is, if the table has values 'system=a module=b block=c' and I query for values 'does the table have system=a module=d block=e' it returns yes, or, to be precise, any_rows_found=1. Value 1 is only not presented when I send a trio that doesn't have one of it's values in the table, for example: 'system=g module=h and block=i'. What is the problem in my query?
Problem is in this:
where system = llt.system
Both systems are the same, it is as if you put where 1 = 1, so Oracle is kind of confused (thanks to you).
What to do? Rename procedure's parameters to e.g. par_system so that query becomes
where llt.system = par_system
Another option (worse, in my opinion) is to precede parameter's name with the procedure name. If procedure's name was e.g. p_test, then you'd have
where llt.system = p_test.system
From the documentation:
If a SQL statement references a name that belongs to both a column and either a local variable or formal parameter, then the column name takes precedence.
So when you do
where system=llt.system
that is interpreted as
where llt.system=llt.system
which is always true (unless it's null). It is common to prefix parameters and local variables (e.g. with p_ or l_) to avoid confusion.
So as #Littlefoot said, either change the procedure definition to make the parameter names different to the column names, or qualify the parameter names with the procedure name - which some people prefer but I find more cumbersome, and it's easier to forget and accidentally use the wrong reference.
Root cause is alias used for table name.
where system=llt.system and module=llt.module and block=llt.block;
Table name alias in select query and input to procedure having the same name(i.e. llt
). You should consider either renaming one of them.
I have a form where people can type in a start and end date, as well as a column name prefix.
In the backend, I want to do something along the lines of
SELECT *, CAST('{{startDate}}' AS TIMESTAMP) AS ({{prefix}} + '_startDate')
Is this possible? Basically, I want to dynamically create the name of the new column. The table is immediately returned to the user, so I don't want to mutate the underlying table itself. Thanks!
You can execute dynamic query that you have prepared by using EXECUTE keyword, otherwise it is not possible to have dynamic structure of SQL.
Since you are preparing your SQL outside database, you can use something like:
SELECT *, CAST('{{startDate}}' AS TIMESTAMP) AS {{prefix}}_startDate
Assuming that {{prefix}} is replaced with some string by your template before it is sent to database.
I would like to implement something like the following pseudo-code. Let say I have table named T_TMP_TABLE with column 'hour', 'day', and 'year'. The table name is used as an input parameter for create_types_fn function. Let's assume that I can get a list of column names and store it to column_name_array. Now, I need to create "custom type" using those column names. The reason is that the function will return table as an output, and the columns of the returned table would be the same ('hour', 'day', and 'year')
Briefly speaking, I have a table and I need output as table-format with same column names.
Am I able to do this? any suggestion or recommendation would be much appreciated!!
CREATE OR REPLACE FUNCTION create_types_fn (table_name in varchar2)
....
begin
array column_name_array = get_column_name_in_array_by_table_name(table_name)
CREATE OR REPLACE TYPE my_type AS OBJECT (
column_name_array(0) NUMBER,
column_name_array(1) NUMBER,
column_name_array(2) VARCHAR2(30)
);
CREATE OR REPLACE type my_table AS TABLE OF my_type ;
select * bulk collect into my_table ;
end
EDIT
Here is what I am trying to do
I am trying to compare two tables and return rows if there are any difference. So, I think the output should be table-format. Since every table has different column names, I think it would be nice if I can make generic function..
If you are trying to compare the data in two different tables, you would almost certainly want to use the dbms_comparison package rather than writing your own. That populates a generic structure rather than creating new types for each table.
I have a table Names
Id Name
+----+---------------+
1 John
2 Kate
3 Mark
I want to create a stored procedure that does the following:
1) take a list of names as string as an input parameter
I have done some researches about this but couldn't find the best way to do it. I will call the stored procedure from the entity framework in a C# application. I was thinking of passing the names in one string separated with a comma and the split them in the procedure. But can't figure out how this is done.
2) for each name in the list, if the name does not exist in the Name column, insert a new row for it.
How can I do a switch case if it exists and insert it if not
3) Select * rows that are in the input list.
After adding all the missing Names, I want to select all the names that were in the input list with their id
Can this be done in one stored procedure, or do I have to divide them into multiple.
I am looking for hints on how to do each step, and if they can be combined.
Thanks
Keep your DB side lean and leave logic on the app side, especially if you have grumpy DBA's.
Use a MERGE/Upsert instead.
Check out this SO post.
If you pass a comma delimited list into a stored procedure as a parameter, you are going to need to understand how to use charindex, left, substring and right
As you split out each name - you would add them into a temporary table or a table valued variable.
Your decision about whether to insert the new names into the Names table would be made using an exists() subquery on an insert statement.
You could then, finally, fashion a select statement to join your temp table/table valued variable back to your Names table to pull out all of the keys (including the new ones) and pass them back to your front end.
I have an application that uses AJAX liberally. I have several places where a single database column is being updated for the record the user is actively editing.
So far I've been creating separate stored procedures for each AJAX action... so I've got UPDATE_NAME, UPDATE_ADDRESS, UPDATE_PHONE stored procedures.
I was just wondering if there's a better way to continue utilizing stored procedures, but without creating one for each column.
I'd like to avoid reflecting upon a string parameter which specifies the column, if possible. I.e. I know I could have an UPDATE_COLUMN procedure which takes as one of its parameters the column name. This kind of gives me the willies, but if that's the only way to do it then I may give it some more considering. But not all columns are of the same data type, so that doesn't seem like a silver bullet.
Consider writing a single update procedure that accepts several columns and uses DEFAULT NULL for all columns that are not mandatory (as suggested by others).
Using NVL in the update will then only update the columns you provided. the only problem with this approach is, that you can't set a value to NULL.
PROCEDURE update_record (
in_id IN your_table.id%TYPE,
in_name IN your_table.name%TYPE DEFAULT NULL,
in_address IN your_table.address%TYPE DEFAULT NULL,
in_phone IN your_table.phone%TYPE DEFAULT NULL,
in_...
) AS
BEGIN
UPDATE your_table
SET name = NVL( in_name, name ),
address = NVL( in_address, address),
phone = NVL( in_phone, phone ),
...
WHERE id = in_id;
END update_record;
You can call it with named parameters then:
update_record( in_id => 123, in_address => 'New address' );
This allows you to update several columns at once when necessary.
I would say to stop using stored procedures for activities that simple, there is no justification to create so many small procedures for every single column in the database. You are much better off with dynamic sql (with parameters) for that.
Create a procedure that can update every column, but only updates columns for which you pass a non-null parameter
CREATE PROCEDURE spUpdateFoo (#fooId INT, #colA INT, #colB VARCHAR(32), #colC float)
AS
update Foo set colA = ISNULL(#colA, colA),
colB = ISNULL(#colB, colB),
colC = ISNULL(#colC, colC)
where fooId = #fooId
Note that this doesn't work if you want to be able to explicitly set null values through your procedure, but you could choose a different value to specify a non-change (-1, etc) with a little more complexity.
It doesn't hurt to do what you are doing, but it could get a little crazy if you continue that path. One thing you can do is create one stored procedure and assign NULL values as default parameters to all your fields that you are updating. So when you call the sproc from your app, if a parameter is given a value that value will be used in the update, otherwise the parameter will take a null value.
Then you can do a check in the sproc IF #Parameter IS NOT NULL ...
If you find yourself ever only needing to update just one field and you do not want to create one central sproc and pass nulls, then use Octavia's solution right below mine and write a simple update procedure.