how to export Data from sql server into csv file using c#
Eg;
Select name,id from employee
Name id
XXX 1
ZZZ 2
AAA 3
This result will be stored in the CSV File.
Using Filehelpers and Dapper.
[DelimitedRecord(",")]
public class Employee
{
public string Name;
public int Id;
}
In some method somewhere:
var employees = connection.Query<Employee>("select Name, Id from employee");
FileHelperEngine engine = new FileHelperEngine(typeof(Employee));
engine.WriteFile("employees.csv", employees);
Related
I have an entity with different fields:
#Entity
public class TestEntity {
private int id;
private String name;
private String description;
#ElementCollection
private Map<String, String> parameter = new HashMap<>();
}
The resulting tables are the following:
TestEntity(id, name, description)
TestEntity_parameter(TestEntity_id, parameter, parameter_KEY)
Now I want to create a named query for this TestEntity that checks if there exists a parameter_KEY of value "test" and with a parameter :parameter.
I tried something like this:
select te from TestEntity te join TestEntity_parameter tep where tep.parameter_KEY = test AND tep.parameter = :parameter
But when I try to deploy, I get an error.
I'm relatively new to hibernate and java ee. Maybe my approach is wrong but I did not find anything how to access the fields of a map with a named query since it creates a new table for that map. So i thought that I need to join those tables.
Hope you guys can help me :)
Thanks a lot :)
Greetings
Simon
You could use the below query.
SELECT te FROM TestEntity te INNER JOIN te.parameter p WHERE KEY(p) = :YOUR_KEY
AND VALUE(p) = :YOUR_VALUE
I want to create objects during the installation of an extension. For example I have the following two simple domain models:
class Product extends AbstractEntity
{
protected $name = '';
protected $sku = '';
...
}
class Location extends AbstractEntity
{
protected $name = '';
protected $city = '';
...
}
and a third domain model like:
class Mapper extends AbstractEntity
{
protected $domainModelName = '';
protected $domainModelProperty = '';
}
Now I want too add entries like this:
domain_model_name | domain_model_property
Product | name
Product | sku
Location | city
....
during the extension installation or directly after the installation, so that the tx_foxexample_domain_model_mapper table will be filled automatically, is this possible?
I know that I can use a initializeAction, but then the entries will only be generated if I add a plugin and visit the page etc., but I want that the entries/ objects already exists before I use a plugin or add some objects.
You can store your static data in the file ext_tables_static+adt.sql which must be located in the root folder of your extension.
According to the TYPO3 API, you must should use the following command to export your static data
mysqldump --password=[password] [database name] [tablename] --add-drop-table > ./ext_tables_static.sql
Also make sure, that the table structure of static tables is present in the ext_tables.sql file.
The extension static_info_tables makes use of this technique. You can have a look at the extension here for more details.
Given a ZIP-code-like hierarchical code/name schema.
For example:
code = 101010
Code:
100000 level 1 code (10....)
101000 level 2 code (..10..)
101010 level 3 code (....10)
Name (short name)
100000 - A
101000 - a
101010 - i
Name (FullQualifiedName)
100000 - A
101000 - A->a
101010 - A-a->i
EDIT
I wanna following code (JPA pseudo code), but CANNOT.
#Entity
public class CodeName{
// ....
String code; // 100101 levels = {100000, 100100, 100101}
String name; //
#HowToMapDirectedToNameOfCode('100000') // #SecondTable ?
String name1;
#HowToMapDirectedToNameOfCode('100100')
String name2;
#HowToMapDirectedToNameOfCode('100101')
String name3;
String getFullQualifiedName(){
return String.format("%s->%s->%s", name1, name2, name3);
}
// getter and setter
}
But it's relatively easier in native SQL:
SELECT (select p1.name from codename p1 where p1.code= concat( substring(p.code,1,2), "0000") ) province,
(select p2.name from codename p2 where p2.code= concat( substring(p.code,1,4), "00") ) city,
(select p3.name from codename p3 where p3.code=p.code) area
FROM codename p WHERE p.code = '100101';
So, I implements it as following snippet.
#Entity
public class CodeName{
// ....
String code; // 100000, 101000, 100101
String name; // province, city , area
#Transient
String name1; // mapping directly?
#Transient
String name2; // mapping directly?
#Transient
String name3; // mapping directly?
String getFullQualifiedName(){
return String.format("%s->%s->%s", name1, name2, name3);
}
// getter and setter
}
public interface CodeNameRepository extends CrudRepository<CodeName, Long>, CodeNameRepositoryCustom {
#Query(" FROM CodeName p " +
" WHERE p.code = CONCAT(SUBSTRING(?1, 1, 2), '0000') " +
" OR p.code = CONCAT(SUBSTRING(?1, 1, 4), '00') " +
" OR p.code = ?1")
List<CodeName> findAllLevelsByCode(String code);
}
#Component
public class CodeNameRepositoryImpl implements CodeNameRepositoryCustom {
#Autowired
private CodeNameRepository codeNameRepository ;
#Override
public CodeName CodeNamefindFullQualifiedNameByCode(String code) {
List<CodeName> codeNames= codeNameRepository .findAllLevelsByCode(code);
CodeName codeName;
// extra name1, name2, name3 from list,
// fill code, name, name1, name2, name3 to codeName and
return codeName;
}
}
But it have SO MANY limitations.
Most likely, I need getFullQualifiedName(), to display it on UI, but every time I must have an extra call to populate all names.
For each entity has CodeName as its children, no matter how deep the codeName is at, I MUST expand to the codeName and reload it with FQN.
Can we mapping all #Transient names directly by JPA?
You could technically model your code repository entity as follows:
public class CodeName {
#Id
#GeneratedValue(GenerationStrategy.AUTO)
#Column
private Long id;
#ManyToOne
private CodeName parent;
#OneToMany(mappedBy = "parent")
private List<CodeName> children;
#Column
private String name;
#Transient
public String getFullyQualifiedName() {
List<String> names = new ArrayList<>();
names.add(name);
CodeName theParent = parent;
while(theParent != null) {
names.add(theParent.getName());
theParent = theParent.parent;
}
Collections.reverse(names);
return StringUtils.join(names, "->");
}
}
Because the parent relationships will be fetched EAGERLY because they mapped as #ManyToOne, you can basically start at any child CodeName entity and traverse up it's parent/child relationship to the root. This basically allows the getFullyQualifiedName method to build the name for you at runtime.
If performance becomes a problem doing this, you can always datamine the names ahead of time in your entity as you described by adding a #Column private String fullyQualifiedName and make sure that field is inserted when you create your codes. Then the transient method I added to my the entity can be dropped since you're caching the names at data insertion.
It is possible to write a JPQL, which is equivalent to your SQL query. The only tricky part is to rewrite nested selects into cross joins, because nested selects are not supported by JPA and you need to join unrelated entities. On the other hand, functions CONCAT and SUBSTRING are supported by JPQL in the same way as in SQL. See the following JPQL query, which should give you the results as the SQL query in the question:
SELECT p1.name // province
, p2.name // city
, p.name // area
FROM CodeName p, CodeName p1, CodeName p2
WHERE p.code = '100101'
AND p1.code = concat( substring(p.code,1,2), "0000")
AND p2.code= concat( substring(p.code,1,4), "00")
The above query will give you 3 values in one row, which cannot be mapped into a single entity. The result of the query will therefore be a list of Object[] arrays. You may also add the original entity into the select clause: SELECT p1.name, p2.name, p.name, p FROM .... This way, you may later process the list of results and assign first three values into the transient fields of the entity:
Object[] rows = query.getResultList();
for (Object row : rows) {
CodeName c = (CodeName)row[3];
c.setName1((String)row[0]);
c.setName2((String)row[1]);
c.setName3((String)row[2]);
}
Using Spring data JPA, trying to create a generic method to upload csv data to database using Load Data mysql. The below code is my attempt. The problem is, the second parameter tablename is getting replaced with quotes. Eg: LOAD DATA LOCAL INFILE Client.csv INTO TABLE 'Client' FIELDS
Any idea on how to overcome this ??
#NoRepositoryBean public interface CustomJpaRepository<T, ID extends Serializable> extends JpaRepository<T, ID> {
#Query(value = "LOAD DATA LOCAL INFILE :filepath INTO TABLE :tablename FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n'", nativeQuery = true)
public void bulkInsertUsingCLI(#Param("filepath") String filepath, #Param("tablename") String tablename);
}
The version of Playframework is 1.2.x,and I want to transform the query.ResultList to VO.
I created a Part entity bean as below:
#Entity
#Table(name="evaluation_part")
public class Part extends Model {
public String name;
public String collegeName;
public int peopleNum;
}
The data:
id name collegeName peopleNum
1 Jsj1 JJJJ 32
2 Jsj2 JJJJ 23
3 Jsj3 JJJJ 32
4 Tjb1 TTTT 11
5 Tjb2 TTTT 14
6 Tjb3 TTTT 16
My value object class:
public class PartVO {
public String collegeName;
public int peopleNum;
}
And I want to use the native query to get the result:
String sql="select collegeName,SUM(peopleNum) as peopleNum from evaluation_part group by collegeName";
The query result is:
collegeName peopleNum
TTTT 41
JJJJ 87
I tried：
String sql="select collegeName,SUM(peopleNum) as peopleNum from evaluation_part group by collegeName";
Query query =JPA.em().createNativeQuery(sql);
List<PartVO> partVOs = query.getResultList();
for(int i=0;i<partVOs.size();i++) {
System.out.println(partVOs.get(i).collegeName);
}
Following error is what i am getting
ClassCastException occured : [Ljava.lang.Object; cannot be cast to valueobject.PartVO
You don't have to user raw sql to do that. With hql you can use the new operator to create your VO (see http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/queryhql.html#queryhql-select)
You have to define a two arg constructor in your partVO class, then you can do
select new package.PartVO(collegeName, SUM(peopleNum)) from Part group by collegeName
Solution 1:Only use 'select new Part()'(constructor defined in the Part class) in the HQL that u can convert object to Part.Hibernate use reflection to automatically inject all the fields u need.
Solution 2:Here the returned type of result must be Object[],so that u can got every field of the record fetched from database by the index of array;
The difference between solution1 and solution2:the previous use constructor in the query and the later transform a record into Object[].
In your case,ignore the complex relationship between entities,solutions above will make work.
Referenced Code here:
package controllers;
import play.*;
import play.db.jpa.JPA;
import play.mvc.*;
import java.util.*;
import models.*;
/**
* This demo is intended for fetching data from MYSQL.
* #author dhl#oopsplay.org
*/
public class Application extends Controller {
public static void index() {
render();
}
/**
* Prepare some data to test.
*/
public static void addPart() {
//Add a part record to database.
Part newPart=new Part("software","zjut",8).save();
if(newPart.isPersistent()){
renderText("Add successfully,there are %s records in the \'evaluation_part\' table.For convenience,please click the back button in the browser to go back previous page.",Part.count());
}
}
/**
* Fetch part entities from database;
*/
public static void fetchPart() {
//-------------------Solution 1-------------------
//[Pay attention]:Only use 'select new Part()'(constructor defined in the Part class) in the query that u can convert object to Part.
//Hibernate use reflection to automatically inject all the fields u need.
List<Part> parts1=JPA.em().createQuery("select new Part(name,collegeName,peopleNum) from Part").getResultList();
//For convenience, i output the detail in the console, focus on the change there.
Logger.info("The name of first record is :%s", parts1.get(0).name);
//-------------------Solution 2-------------------
//[Pay attention]:Here the returned type of result must be Object[],so that u can got every field of the record fetched from database;
List<Object[]> parts2=JPA.em().createNativeQuery("select name,collegeName,peopleNum from evaluation_part").getResultList();
Logger.info("The name of first record is :%s", parts2.get(0)[0]);
for(int i=0;i<parts2.size();i++){
//The difference between solution1 and solution2:the previous use constructor in the query and the later transform a record into Object[].
Logger.info("Name from parts1 is: %s", parts1.get(i).name);
Logger.info("Name from parts2 is: %s", parts2.get(i)[0]);
}
renderText("There are %s record in the \'evaluation_part\' table",parts2.size());
}
}
You can use the version of createNativeQuery(...) method that also accepts as argument the Class of the result instance(s):
http://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#createNativeQuery(java.lang.String, java.lang.Class).
However make sure this actually works, as Play Framework doesn't implement all the features of JPA in it's implementation of the API.