Develop Reference

Dynamically build SQL where clause based on presence of attributes in DTO

I have a screen where users can search a table based on 1 or more of its columns. I am passing the columns the users would like to filter by as a DTO to the backend.
There I am building a SQL to query by checking for the presence of these fields in the DTO...
Object transactionSearch (TransactionSearchDTO dto ){
StringBuilder transactionQuery = new StringBuilder()
transactionQuery.append("SELECT id, delivery_date, order_date, customer_name FROM transaction where 1=1 ")
if (dto.order_id) {
transactionQuery.append("and order_id = ${dto.order_id}")
}
if (delivery_date) {
transactionQuery.append("and order_id = ${delivery_date}")
}
if (customer_name) {
transactionQuery.append("and order_id = ${customer_name}")
}
}
What I am ending up with is a ton of if statements for each column.
Is there a way to achieve this without having an if block per filter?
I found some ideas here but I need a solution in Groovy or Java.

i suggest to use GString instead of StringBuilder to pass parameters correctly to groovy.sql.Sql
class DTO{
int id
String name
Date created
}
def a = new DTO(id:123, created:new Date())
GString f(DTO a){
GString q = GString.EMPTY + 'select ' + a.getProperties().collect{k,v-> k}.join(',')+' from T'
a.getProperties().each{k,v->
if(k!='class' && v!=null){
q = q + ( q.getValueCount()==0 ? ' WHERE ' : ' AND ' )
q = q + k + " = ${v}"
}
}
return q
}
def s = f(a)
println s
println s.getValues()
println s.getStrings()

Android SQLite rawQuery - How to select multiple rows of a table

I'm trying to use rawQuery to return a cursor with a few different rows of data to be passed into it. When there is only 1 argument it works. When there is more than 1 argument it displays the empty ListView state. I believe the issue lies here:
// Query for items from the database and get a cursor back. Edited code for clarity:
recipeCursor = db.rawQuery("SELECT course, name, _id " +
" FROM recipes WHERE _id = ?",
selectedRecipesSQL);
When the code works the selectedRecipesSQL would look something like:
String[] selectedRecipesSQL;
selectedRecipesSQL = new String[]{"2"};
And when it doesn't work it would be something like
String[] selectedRecipesSQL;
selectedRecipesSQL = new String[]{"2 OR 5"};
So, to be clear, I can display a single row of the table in my ListView, but if I try to display more than one row of the table then it won't display anything.
One ugly solution which has crossed my mind (but I haven't pursued) is that I need to edit the rawQuery selection statement to read something like:
recipeCursor = db.rawQuery("SELECT course, name, _id " +
" FROM recipes WHERE _id = ? OR _id = ? OR _id = ?",
selectedRecipesSQL);
I'd probably use a for loop to generate the correct amount of WHERE "_id = ?" and then use a string array:
selectedRecipesSQL = new String[]{"2", "5"};

One way of doing it is by passing the possible values of _id as 1 string which is a comma separated list like this:
selectedRecipesSQL = new String[]{"1,2,3"};
and in your query use the operator LIKE:
recipeCursor = db.rawQuery(
"SELECT course, name, _id FROM recipes WHERE ',' || ? || ',' LIKE '%,' || _id || ',%'",
selectedRecipesSQL
);
This works also for just 1 value.

static String multiply__concat_string(String text,String joiner_,int multiple_)
{
String output="";
for(int i=0;i<multiple_;i++)
{
output+=(text+joiner_);
}
if(output.length()>0)
{
output=output.substring(0,output.length()-1);
}
return output;
}
Use it like this :
selectedRecipesSQL = new String[]{"2", "5"};
db.rawQuery("SELECT course, name, _id " +
" FROM recipes WHERE _id IN("+multiply_concat_string("?",",",selectedRecipesSQL.length)+")",
selectedRecipesSQL);

How to get number of particular name in sqlite table by query

I have a table in which name and number of people are stored. Now I want to make a method in sqlite helper class which will return the number of particular person whose name I will pass in the method
There is something wrong with my code.
Here is my code
public String fetchGroup(SQLiteDatabase inDatabase, String valueCheck){
String query = "SELECT * FROM groups WHERE groupname='" + valueCheck;
Cursor cursor = inDatabase.rawQuery(query,null);
String place = cursor.getString(cursor.getColumnIndex("contactid"));
return place;

Take care to use cursor.moveToFirst() command before reading datas
Else, instead counting the number of people in Java, you can just modify your query to have only this number return.
Something like this :
public String fetchGroup(SQLiteDatabase inDatabase, String valueCheck){
String query = "SELECT COUNT(id) FROM groups WHERE groupname=\"" + valueCheck + "\"";
Cursor cursor = inDatabase.rawQuery(query, null);
cursor.moveToFirst();
int place = cursor.getInt(0);
return String.valueOf(place);
}

After your query do
int count = 0;
while (cursor.moveToNext()) {
// increment variable
count++;
}
after iterating you will get number of count

how to generate sql query dynamically having specific colums

I have several tables. I have a query also. My problem is to generate the SQL query dynamically using Java.
I have the following fields in a separate table:
Collumn name status
po_number, Y
unit_cost, Y
placed_date , Y
date_closed, Y
scheduled_arrival_date Y
date_closed Y
order_quantity Y
roll_number N
product_sku N
product_category_name N
rec_vendor_quantity Y
vendor_name Y
et_conversion_unit_quantity Y
from which i have to generate a query when the status is Y, the problem here is some time the above columns
The following query is the out put of the above :
here i have inculded all the columns but i have to exculde the column which has the status of N, please help me to construt the query using java.
select
pi.po_number,poi.unit_cost,pi.placed_date CreateDate,
case when isnull(pi.date_closed) then pi.scheduled_arrival_date
else pi.date_closed end as ReceviedDate,
poi.order_quantity,poi.roll_number,p.product_sku product_name,
pc.product_category_name,poi.rec_vendor_quantity,pv.vendor_name,p.et_conversion_unit_quantity,pi.note
from
purchase_order as pi,
purchase_order_inventory as poi,
product_vendors as pv,
products AS p,
product_categories AS pc
where
pi.purchase_order_id=poi.purchase_order_id and
pc.product_category_id=p.product_category_id and
poi.product_id = p.product_id and
poi.product_category_id=pc.product_category_id and
pi.vendor_id=pv.product_vendor_id and
( ( pi.date_closed >= '2012-01-01' and pi.date_closed <='2012-09-05 23:59:59' )
or ( pi.scheduled_arrival_date >= '2012-01-01' and pi.scheduled_arrival_date <='2012-09-05 23:59:59') ) and
pi.po_type=0
and pi.status_id = 0 and poi.transaction_type = 0
order by pi.po_number
UPDATE :
QUERY : STEP 1:
SELECT rcm.id,rcm.tablename,rcm.columnname,rcm.size,rcm.displayorder,rcm.isactive FROM report_customise_master rcm where rcm.tablename !='employee' and rcm.isactive='Y' order by rcm.displayorder;
STEP 2 :
Java method to construct the query :
public Map getComplexReportQuery() {
String query = "SELECT rcm.id,rcm.tablename,rcm.columnname,rcm.size,rcm.displayorder,rcm.isactive FROM report_customise_master rcm where rcm.tablename !='employee' and rcm.isactive='Y' order by rcm.displayorder;";
String tableName = "", from = "", select = "";
StringBuffer sb = new StringBuffer();
Map<String, List<String>> resultsMap = new LinkedHashMap<String, List<String>>();
Map<String, String> displayOrderMap = new LinkedHashMap<String, String>();
Map queryMap = new LinkedHashMap();
if (!query.isEmpty() || query.length() > 0) {
sb.append(query);
}
Connection connection = getConnection();
if (connection != null) {
try {
PreparedStatement reportQueryPS = connection.prepareStatement(sb.toString());
ResultSet reportQuery_rst = reportQueryPS.executeQuery();
List<String> tables = new ArrayList<String>();;
if (reportQuery_rst != null) {
StringBuilder selectQuery = new StringBuilder(" SELECT ");
StringBuilder fromQuery = new StringBuilder(" FROM ");
while (reportQuery_rst.next()) {
tableName = reportQuery_rst.getString("tablename");
List<String> columns = resultsMap.get(tableName);
if (columns == null) {
columns = new ArrayList<String>();
resultsMap.put(tableName, columns);
}
columns = resultsMap.get(tableName);
String columnName = reportQuery_rst.getString("columnname");
columns.add(columnName);
}
tableName = "";
for (Entry<String, List<String>> resultEntry : resultsMap.entrySet()) {
tableName = resultEntry.getKey();
List<String> columns = resultEntry.getValue();
int i = 0;
for (String column : columns) {
selectQuery.append(tableName + "." + column);
if (i != columns.size()) {
selectQuery.append(",");
} else {
selectQuery.append("");
}
i++;
}
if (!tables.contains(tableName)) {
tables.add(tableName);
}
}
//to remove comma at the end of line
select = selectQuery.toString().replaceAll(",$", "");
tableName = "";
int i = 0;
for (String table : tables) {
fromQuery.append(table);
fromQuery.append(" ");
fromQuery.append(table);
if (i != tables.size()) {
fromQuery.append(",");
} else {
fromQuery.append("");
}
i++;
}
from = fromQuery.toString().replaceAll(",$", "");
queryMap.put("query", select + from);
}
//from = from+"ORDER BY "+orderbyColumn+" "+sort+" ";
} catch (Exception ex) {
ex.printStackTrace();
} finally {
try {
closeConnection(connection, null, null);
} catch (Exception ex) {
ex.printStackTrace();
}
}
} else {
System.out.println("Connection not Established. Please Contact Vendor");
}
return queryMap;// return the map/ list which contains query and sory and display order
}
STEP 3 : Result query
{query= SELECT purchase_order.po_number,purchase_order.placed_date,purchase_order.date_closed,purchase_order.scheduled_arrival_date,purchase_order_inventory.unit_cost,purchase_order_inventory.order_quantity,purchase_order_inventory.roll_number,purchase_order_inventory.rec_vendor_quantity,products.product_sku,products.et_conversion_unit_quantity,product_categories.product_category_name ,product_vendors.vendor_name FROM purchase_order purchase_order,purchase_order_inventory purchase_order_inventory,products products,product_categories product_categories,product_vendors product_vendors}
but this not what i wanted, Please help me to construct the query i have given.

Two queries
You need to make two queries:
Query which fields are enabled
Build the second query string (the one you want to build dinamically)
It's this way because a SQL query has to tell which columns will be included before querying any data. In fact it will be used to build the internal DB query plan, it is, the way the DB motor will use to retrieve and organize the data you ask.
Query all columns
Is it necesary to query only that fields? Can't you query everything and use the relevant data?
Joins
Looking at the updated question I guess you need to dynamically add where conditions to join tables correctly. What I should do is have a reference telling me what coindition to add when a table is present.
There are at least two options:
Based on table pairs present (by example: "if A and B are present then add A.col1 = B.col2")
Based on tables present ("if B is present, then add A.col1 = B.col2; A should be present"
Based on your example I think the second option is more suitable (and easy to implement).
So I should have some static Map<String, JoinInfo> where JoinInfo has at least:
JoinInfo
+ conditionToAdd // by example "A.col1 = B.col2"
+ dependsOnTable // by example "A" to indicate that A must be present when B is present
So you can use:
that info to add tables that should be (by example: even if A has no selected cols, must be present to join with B)
include the conditionToAdd to the where clause
Anyway... I think you are getting into much trouble. Why so dynamic?

You have to approach the thing step by step.
Firstly you have to create a query that will return all rows that have status='Y'
Then you will put the COLUMN_NAME in a list of Strings.
List<String> list = new List<String>();
while(rs.next()){
list.add(rs.getString(columnNumber));
}
And then you have to loop the List and generate dynamically your second sql statement
String sqlSelect = "SELECT ";
String sqlFrom = " FROM SOME_OTHER_TABLE "
String sqlWhere = " WHERE SOME_CONDITION = 'SOME_VALUE' "
for(String x : list){
sqlFrom += x +" , "+;
}
//here make sure that you remove the last comma from sqlFrom because you will get an SQLException
String finalSql = sqlSelect + sqlFrom + sqlWhere ;

Hibernate and Mysql results don't match

I 'm using Hibernate connecting to mysql as database layer, the weird thing is for some reason
the result sets executed from Hibernate api java code are different from those executed directly from mysql. They are not a part of each other, they just look like no relationship.
Here's the Java code at Dao layer:
int totalPage = 0;
int reminder = total % pagination.getPageSize();
if(total == 0){
totalPage = 1;
pagination.setTotalPage(totalPage);
}else{
totalPage = reminder == 0 ? total / pagination.getPageSize() : (total - reminder) / pagination.getPageSize() + 1;
pagination.setTotalPage(totalPage);
}
pagination.setTotalRows(total);
pagination.setBeginAndEndPage(total);
final StringBuilder queryString = new StringBuilder();
queryString.append(" select a.target_id as itemId, a.isFree as isFree, ");
queryString.append(" ni.fullName as item, nc.fullName as category, a.downloadCount as downloadCounts from( ");
queryString.append(" select dldc.current_category_id, dldc.target_id, dldc.isFree, ");
queryString.append(" sum(dldc.counts) as downloadCount from download_log_day_count dldc ");
queryString.append(" group by dldc.current_category_id, dldc.target_id) as a ");
queryString.append(" left join item i on a.target_id = i.objectId ");
queryString.append(" left join name ni on i.nameId = ni.objectId ");
queryString.append(" left join category c on a.current_category_id = c.objectId ");
queryString.append(" left join name nc on c.nameId = nc.objectId ");
queryString.append(" order by downloadCounts desc");
List<ItemReportVO> reportList = (List<ItemReportVO>)getJpaTemplate().execute(new JpaCallback(){
#Override
public Object doInJpa(EntityManager em)
throws PersistenceException {
SQLQuery query = ((Session)em.getDelegate()).createSQLQuery(queryString.toString());
query.addScalar("itemId", Hibernate.LONG);
query.addScalar("isFree", Hibernate.BOOLEAN);
query.addScalar("item", Hibernate.STRING);
query.addScalar("category", Hibernate.STRING);
query.addScalar("downloadCounts", Hibernate.LONG);
query.setResultTransformer(Transformers.aliasToBean(ItemReportVO.class));
int firstResult = (pagination.getCurrentPage()-1) * pagination.getPageSize();
query.setFirstResult(firstResult);
if(token != null && "all".equals(token)){
int maxResult = pagination.getPageSize();
query.setMaxResults( maxResult );
}else{
int maxResult = pagination.getPageSize() > Integer.valueOf(token) ? Integer.valueOf(token) : pagination.getPageSize();
query.setMaxResults( maxResult );
}
return query.list();
}
});
When I set show_sql=true in Hibernate's config file, Hibernate prints the sql query below when Java code runs "return query.list();":
select a.target_id as itemId, a.isFree as isFree, ni.fullName as item, nc.fullName as category, a.downloadCount as downloadCounts
from(
select dldc.current_category_id, dldc.target_id, dldc.isFree, sum(dldc.counts) as downloadCount
from download_log_day_count dldc
group by dldc.current_category_id, dldc.target_id) as a
left join item i on a.target_id = i.objectId
left join name ni on i.nameId = ni.objectId
left join category c on a.current_category_id = c.objectId
left join name nc on c.nameId = nc.objectId
order by downloadCounts desc
limit ?
I always consider they should be the same, but it seems they are not, anybody can help me to adjust the java codes?

Hibernate will alter your query to apply limit that you coded via API setMaxResults(). It should also add rownum> for setFirstResult() but, in your case, it may be very first query.
You don't have to change anything as Hibernate applies those in database specific and correct way.
Is there any other difference that concerns you?