I successfully created the Database and inserted a row however I cannot Query it for some reason. My Droid crashes everytime.
// Create a new row of values to insert.
ContentValues newValues = new ContentValues();
// Assign values for each row.
newValues.put("value", "kunjan");
// Insert the row into your table
myDatabase.insert(DATABASE_TABLE, null, newValues);
String[] result_columns = new String[] { "value" };
// I GET AN EXCEPTION HERE
Cursor allRows = myDatabase.query(true, DATABASE_TABLE, result_columns, null, null,
null, null, null, null);
if (allRows.moveToFirst()) {
String value = allRows.getString(0);
TextView foo = (TextView) findViewById(R.id.TextView01);
foo.setText(value);
}
allRows.close();
myDatabase.close();
I get this exception
no such column: value: , while compiling: SELECT DISTINCT value FROM mainTable
I think you are creating table with only one column(value) and you are trying to read the column-1 instead of column-0 from the cursor. If that still not helps, please add try-catch block and capture the logs
String value = allRows.getString(0);
Some of the problems with the original post
Creating a table that has already been created. I wrote "if not exists" in the "create table" instruction.
Not handling Exceptions properly. I got a lot of exceptions in the creation of the table, quering it etc. I sorrounded all these operations with try-catch
Using hard coded values for Column names - This made it harder to verify if I was querying the column that I had created.
Related
I am not sure if this is possible but I have not been able to come across clear documentation for this use case. I am using F# 4 and the FSharp.Data.SqlClient library to connect to SQL Server 2016. I am wanting to call a stored procedure that returns multiple tables and turn those tables into the corresponding records. In this case the first table is made up of items and the second table is made up of customers.
My instinct is that it should look something like this:
let items, customers = cmd.Execute()
My gut is that items would be an IEnumerable<item> and customers would be an IEnumerable<customer> where item and customer are both Record types. What it appears is happening though is that FSharp.Data.SqlClient is only seeing the first returned table from the stored procedure. I am working on a SQL Server 2016 Developer instance. Here is the T-SQL to setup the example:
create table Item (
ItemID int identity(1, 1) primary key,
ItemName nvarchar(50)
)
go
create table Customer (
CustomerID int identity(1, 1) primary key,
CustomerName nvarchar(50)
)
go
insert into Item (ItemName) values ('A');
insert into Item (ItemName) values ('B');
insert into Item (ItemName) values ('C');
insert into Customer (CustomerName) values ('Gary');
insert into Customer (CustomerName) values ('Sergei');
insert into Customer (CustomerName) values ('Elise');
go
create procedure dbo.ExampleProcedure
as
begin
set nocount on;
select
ItemID,
ItemName
from Item
select
CustomerID,
CustomerName
from Customer
end;
And here is the F# script that I am testing with. It shows what I would like to be able to do but I get a compile error on the last line:
#r "../packages/FSharp.Data.SqlClient.1.8.2/lib/net40/FSharp.Data.SqlClient.dll"
#r "../packages/FSharp.Data.2.3.2/lib/net40/FSharp.Data.dll"
#r "System.Xml.Linq.dll"
open FSharp.Data
[<Literal>]
let connStr =
"Data Source=**connection string**;"
type queryExample = SqlProgrammabilityProvider<connStr>
do
use cmd = new queryExample.dbo.ExampleProcedure(connStr)
let items, customers = cmd.Execute()
I am wanting items to correspond to the first returned table and customers to correspond to the second returned table. The intellisense suggests that FSharp.Data.SqlClient is only seeing the first table. When I hover over cmd.Execute() the popup says "This expression was expected to have type 'a*'b but here has type System.Collections.Generic.IEnumerable<SqlProgrammabilityProvider<...>.dbo.ExampleProcedure.Record>". If I do the following I get access to the Items query in the stored procedure:
// Learn more about F# at http://fsharp.org. See the 'F# Tutorial' project
// for more guidance on F# programming.
#r "../packages/FSharp.Data.SqlClient.1.8.2/lib/net40/FSharp.Data.SqlClient.dll"
#r "../packages/FSharp.Data.2.3.2/lib/net40/FSharp.Data.dll"
#r "System.Xml.Linq.dll"
open FSharp.Data
[<Literal>]
let connStr =
"Data Source=**connection string**;"
type queryExample = SqlProgrammabilityProvider<connStr>
do
use cmd = new queryExample.dbo.ExampleProcedure(connStr)
for item in cmd.Execute() do
printfn "%A" item.ItemID
Is this even possible? Is my approach wrong? I could not find clear documentation on this use case but I thought it would be common enough it would be covered.
Update
Just to clarify what I am trying to achieve I am showing how I solve this in C#. In C# I create a DataSet object and populate it with the results of the Stored Procedure. From there I pick out the individual tables to work with. After extracting the tables I then use LINQ to transform the rows into the corresponding objects. It often looks something like the following:
using System.Data;
using System.Data.SqlClient;
var connStr = "**connection string**"
var sqlConnection = new SqlConnection(connStr );
var sqlCommand = new SqlCommand("ExampleProcedure", sqlConnection);
sqlCommand.CommandType = CommandType.StoredProcedure;
var dataSet = new DataSet();
var adapter = new SqlDataAdapter(sqlCommand);
adapter.Fill(dataSet);
var itemsTable = dataSet.Tables[0];
// Turn the itemsTable into a List<Item> using LINQ here
var customersTable = dataSet.Tables[1];
// Turn the customersTable into List<Customer> using LINQ here
I find this to be overly verbose for such a simple thing as extracting the individual tables but perhaps I am too sensitive to code clutter. I know that F# must have a more elegant and terse way to express this.
I don't know F#, however this is a data access problem.
When a stored procedure returns multiple resultsets, you need to access they in sequence, one by one.
cmd.ExecuteReader() returns an instance of a datareader pointing to the first resultset. You need to process this resultset, may be filling a list with instances of a custom class, than you call the method "NextResult" and you will have access to the next resultset and so on.
A reference for the method "NextResult": https://msdn.microsoft.com/pt-br/library/system.data.sqlclient.sqldatareader.nextresult(v=vs.110).aspx
I am using SQL Server 2016.
I have a stored procedure GET_RECORDS that takes input parameters for filter and outputs a CURSOR parameter
I want to get this cursor in my SSIS package
I had created data flow task, OleDb source and variables for parameter values. Then mapped parameters
Params mapping screen
but when I wanted to save the component - I got an error
error screen
I tried to add clause WITH RESULT SETS with some dummy columns, but my procedure doesn't return any result set
What am I doing wrong?
Any advices will be helpful.
Thank you.
With regards, Yuriy.
The source component is trying to determine what columns and types will be returned. Because you are using dynamic SQL the metadata can change each time you run it.
With result sets allows you to define the data being returned but should only be used if you are guaranteed to have those results every time you execute.
EDIT:
I create a connection and run the command so that it populates a data table. Then I put the column headers into a string array. There are plenty of examples out there.
Then I use the following function to create a destination table. Finally I create a datareader and pass that to the .Net SqlBulkCopy. Hope this helps.
private void CreateTable(string TableName, string[] Fields)
{
if (TableExists(TableName) && Overwrite)
{
SqlCommand = new SqlCommand($"Drop Table [{TableName}]", SqlConnection);
SqlCommand.ExecuteNonQuery();
}
string Sql = $"Create Table [{TableName}] (";
int ColumnNumber = 1;
foreach (string Field in Fields)
{
string FieldValue = Field;
if (! HasHeaders)
{
FieldValue = "Column" + ColumnNumber;
ColumnNumber++;
}
Sql += $"[{FieldValue}] Varchar(8000),";
}
Sql = Sql + "ImportFileID Int, ID Int Identity(1,1) Not Null, Constraint [PK_" + TableName + "] Primary Key Clustered ([ID] Asc))";
SqlCommand = new SqlCommand(Sql, SqlConnection);
SqlCommand.ExecuteNonQuery();
}
Use ado.net source instead of oledb source, define a simple select and get the columns you wish to return. Now you can define expresión in the dataflow properties.
Search ado.net source dynamic sql
:)
try to return the records and use foreach in ETL instead of cursor
https://www.simple-talk.com/sql/ssis/implementing-foreach-looping-logic-in-ssis/
I think you can do it from a simple way, but I don't know what you are you doing, exactly...
Jdev Version : 11.1.1.7
I have created a Department VO based Department EO with the following query :
SELECT DeptEO.DEPARTMENT_ID,
DeptEO.DEPARTMENT_NAME,
DeptEO.MANAGER_ID,
DeptEO.LOCATION_ID,
DeptEO.ACTIVE
FROM DEPARTMENTS DeptEO where DeptEO.DEPARTMENT_ID > 250
UNION
SELECT 280 , 'Advertising',200,1700,'Y' from Dual
For the simplicity , I have used a sample statement from dual table , in real scenario , the query after UNION clause will populate from a table.
After running the query ,I get the result that is desired on the UI .
Now my requirement is to insert this newly created row with DEPARTMENT_ID as 280 , into DB table DEPARTMENTS.
While committing , ADF throws error as " oracle.jbo.RowAlreadyDeletedException: JBO-29114 " which is correct as the this row is missing from DB table , so when it goes for taking a lock on the row for update , it doesn't find anything .
Is there any way that i can instruct ADF to consider this row for Insert rather than update .
We also tried to populate the data of this row into a new row instance created from RowSetIterator , and afterwards remove the culprit row by calling removeFromCollection() and then inserting the duplicated row , but still no luck .
Other approaches that we are thinking of are :
1- Create another VO/EO and insert values in table through them .
2- Create a DB View for this query and trigger on this view , so when ever an update operation comes , we do our logic in trigger i.e. decide whether to update or insert the data.
Can you please guide what should be done in such scenario .
Regards,
Siddharth
Edit : Code for Inserting Row (What I was trying but it's not working)
RowSetIterator rsi=iterator.getRowSetIterator();
Row editableRow= rsi.createRow();
while(rsi.hasNext()){
Row r =rsi.next();
if((""+r.getAttribute("DepartmentId")).toString().equals("280") ){
System.err.println("? Equality row found!!!");
editableRow.setAttribute("DepartmentId", r.getAttribute("DepartmentId"));
editableRow.setAttribute("DepartmentName", r.getAttribute("DepartmentName"));
editableRow.setAttribute("ManagerId", r.getAttribute("ManagerId"));
editableRow.setAttribute("LocationId", r.getAttribute("LocationId"));
editableRow.setAttribute("Active", r.getAttribute("Active"));
rsi.removeCurrentRowFromCollection();
}
}
if(editableRow !=null){
System.err.println("? Row value after removal : "+editableRow.getAttribute("DepartmentName"));
rsi.insertRow(editableRow);
operBindingCommit.execute();
}
Your use case can be implemented in a couple of ways. First way is to iterate over row set in managed bean and check if department with id 280 exists, if yes then update the row otherwise invoke Create with parameters for department VO. The second way, and would say the better way, is to create a method for update/insert at business component level, either in ViewObjectImpl or in ApplicationModuleImpl and then invoke it from managed bean.
Here is the sample code for insert/update method written in VOImpl
public void updateInsertJobs(String jobId, String jobTitle,
String minSalary, String maxSalary)
{
RowSetIterator rSet = this.createRowSetIterator(null);
JobsViewRowImpl row = new JobsViewRowImpl();
Boolean jobExist = false;
if (null != jobId)
{
try
{
while (rSet.hasNext())
{
row = (JobsViewRowImpl) rSet.next();
if (row.getJobId().equals(jobId))
{
row.setJobTitle(jobTitle);
row.setMinSalary(new Number(minSalary));
row.setMaxSalary(new Number(maxSalary));
jobExist = true;
}
}
if (!jobExist)
{
JobsViewRowImpl r = (JobsViewRowImpl) this.createRow();
r.setJobId(jobId);
r.setJobTitle(jobTitle);
r.setMinSalary(new Number(minSalary));
r.setMaxSalary(new Number(maxSalary));
this.insertRow(r);
}
this.getDBTransaction().commit();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
Make sure to expose the method in Client Interface in order to be able to access it from data control.
Here is how to invoke the method from managed bean:
public void insertUpdateData(ActionEvent actionEvent)
{
BindingContainer bc =
BindingContext.getCurrent().getCurrentBindingsEntry();
OperationBinding oB = bc.getOperationBinding("updateInsertJobs");
oB.getParamsMap().put("jobId", "TI_STF");
oB.getParamsMap().put("jobTitle", "Technical Staff");
oB.getParamsMap().put("minSalary", "5000");
oB.getParamsMap().put("maxSalary", "18000");
oB.execute();
}
Some references which could be helpful:
http://mahmoudoracle.blogspot.com/2012/07/adf-call-method-from-pagedefinition.html#.VMLYaf54q-0
http://adftidbits.blogspot.com//2014/11/update-vo-data-programatically-adf.html
http://www.awasthiashish.com/2012/12/insert-new-row-in-adf-viewobject.html
Your view object become readonly due to custom sql query.
However you still can create row in dept table using entity.
Create java implemetation including accessors for DeptEO.
Create custom method in view object and create new entity or update existing using entity definition there. To find that required row exist, you can check that entity with this key is already exists. Something like this (assuming deptId is your primary key):
public void createOrUpdateDept(BigInteger deptId){
DeptEOImpl dept;
EntityDefImpl deptDef = DeptEOImpl.getDefinitionObject();
Key key = new Key(new Object[]{deptId});
dept = deptDef.findByPrimaryKey(getDBTransaction(), key);
if (dept == null){
// Creating new entity if it doesn't exist
dept = deptDef.createInstance2(getDBTransaction(), null);
dept.setDepartmentId(deptId);
}
// Changing other attributes
dept.setDepartmentName("New name");
// Commiting changes and refreshing ViewObject if required
getDBTransaction().commit();
executeQuery();
}
This code is just a sample, use it as reference/idea, don't blindly copy/paste.
I'm using a strongly typed DataSet and I fill all Tables of the DataSet at the beginning of the program. I have one table that can be changed by multiple users. Sometimes it happens that this table is changed outside of the dataSet, so that the user does not have the newest version of the table and gets an Exception when trying to insert the same row.
my procedure:
When a user wants to insert a new row I check the dataset for the existence of the row and only insert the row if it is not already there. But in the meantime (between filling and checking) it happens that another user inserts the same row into the database. So I get the SQLException: Violation of PRIMARY KEY constraint (error 2627).
How can I avoid this?
Thats how I check if the row is already part of database:
customersTableAdapter custAdapter = new customersTableAdapter();
AzureDataSet.customersRow custRow= azureDataSet.customers.FindBycustID(hash);
if(custRow==null)
{
try
{
custRow= azureDataSet.customers.NewcustomersRow();
custRow.custID = hash;
azureDataSetcustomers.AddcustomersRow(custRow);
retryPolicy.ExecuteAction(() =>
{
customersTableAdapter.Update(azureDataSet.customers);
});
}
catch
{
//check for error 2627??
}
}
return custRow.custID;
The problem is that TableAdapters do not provide a data synchronisation.
I wrote a stored procedure to insert the data and checked in the stored procedure if the value is already there.
I also catched a duplicate key exception which migth still occur, because of the delay between the check and the insert operation.
I am trying to use Dapper support my data access for my server app.
My server app has another application that drops records into my database at a rate of 400 per minute.
My app pulls them out in batches, processes them, and then deletes them from the database.
Since data continues to flow into the database while I am processing, I don't have a good way to say delete from myTable where allProcessed = true.
However, I do know the PK value of the rows to delete. So I want to do a delete from myTable where Id in #listToDelete
Problem is that if my server goes down for even 6 mintues, then I have over 2100 rows to delete.
Since Dapper takes my #listToDelete and turns each one into a parameter, my call to delete fails. (Causing my data purging to get even further behind.)
What is the best way to deal with this in Dapper?
NOTES:
I have looked at Tabled Valued Parameters but from what I can see, they are not very performant. This piece of my architecture is the bottle neck of my system and I need to be very very fast.
One option is to create a temp table on the server and then use the bulk load facility to upload all the IDs into that table at once. Then use a join, EXISTS or IN clause to delete only the records that you uploaded into your temp table.
Bulk loads are a well-optimized path in SQL Server and it should be very fast.
For example:
Execute the statement CREATE TABLE #RowsToDelete(ID INT PRIMARY KEY)
Use a bulk load to insert keys into #RowsToDelete
Execute DELETE FROM myTable where Id IN (SELECT ID FROM #RowsToDelete)
Execute DROP TABLE #RowsToDelte (the table will also be automatically dropped if you close the session)
(Assuming Dapper) code example:
conn.Open();
var columnName = "ID";
conn.Execute(string.Format("CREATE TABLE #{0}s({0} INT PRIMARY KEY)", columnName));
using (var bulkCopy = new SqlBulkCopy(conn))
{
bulkCopy.BatchSize = ids.Count;
bulkCopy.DestinationTableName = string.Format("#{0}s", columnName);
var table = new DataTable();
table.Columns.Add(columnName, typeof (int));
bulkCopy.ColumnMappings.Add(columnName, columnName);
foreach (var id in ids)
{
table.Rows.Add(id);
}
bulkCopy.WriteToServer(table);
}
//or do other things with your table instead of deleting here
conn.Execute(string.Format(#"DELETE FROM myTable where Id IN
(SELECT {0} FROM #{0}s", columnName));
conn.Execute(string.Format("DROP TABLE #{0}s", columnName));
To get this code working, I went dark side.
Since Dapper makes my list into parameters. And SQL Server can't handle a lot of parameters. (I have never needed even double digit parameters before). I had to go with Dynamic SQL.
So here was my solution:
string listOfIdsJoined = "("+String.Join(",", listOfIds.ToArray())+")";
connection.Execute("delete from myTable where Id in " + listOfIdsJoined);
Before everyone grabs the their torches and pitchforks, let me explain.
This code runs on a server whose only input is a data feed from a Mainframe system.
The list I am dynamically creating is a list of longs/bigints.
The longs/bigints are from an Identity column.
I know constructing dynamic SQL is bad juju, but in this case, I just can't see how it leads to a security risk.
Dapper request the List of object having parameter as a property so in above case a list of object having Id as property will work.
connection.Execute("delete from myTable where Id in (#Id)", listOfIds.AsEnumerable().Select(i=> new { Id = i }).ToList());
This will work.