I'm handling random tables from a database, I have a field with table's schema, and another with table's name, that way I'm able to do a table input like the following inside a child transformation:
SELECT * FROM ${SCHEMA}.${TABLENAME};
After getting the table values as columns, I want to dynamically generate an SQL with dynamic WHERE clauses, with something like this within a User Defined Java class:
Object[] in = getRow();
String sql = String.format("SELECT %s FROM %s.%s WHERE ",
getParameter("KEYS"),
getParameter("SCHEMA"),
getParameter("TABLE"));
Object[] out = createOutputRow(in, data.outputRowMeta.size());
ArrayList<String> fieldNames = new ArrayList<String>(Arrays.asList(data.inputRowMeta.getFieldNames()));
for(String field: fieldNames){
sql += String.format("\"%s\" = \'%s\' AND ", field, get(Fields.In, field).getString(in));
get(Fields.Out, field).setValue(out, get(Fields.In, field).getString(in));
}
sql = sql.substring(0, sql.length()-4);
sql += ";";
Resulting in a column like this:
SELECT keys, from, the, table FROM SCHEMA.TABLE WHERE "unknown_field" = 'value' AND "unknown_field_1" = '0';
Now, that's all good until I receive a non String type from the SELECT, where I can't do get(Fields.In, field).getString(in)
since it returns
Conversion error: field Integer(9): There was a data type error: the data type of java.lang.String.object [0] does not correspond to value meta [Integer (9)]
Can you change every unspecified field's meta type? If not, is there a way to cast every non String field type within the custom Java Class to String?
Related
Currently, I have a GORM query that calculates a counter for each table entry using a second table and returns the first table with a new field "locks_total" which doesn't exist in the original.
Now, what I want to achieve is the same table returned (with the new "locks_total" field) but filtered with "locks_total" = 0.
I can't seem to make it happen because it doesn't recognize this field in the table, what can I do to make it happen? is it possible to run the query and then execute the filter on the new result table?
This is how we currently do it-
txn := dao.postgresManager.DB().Model(&models.SecretMetadataResponse{})
txn.Table(dao.firstTableName + " as s").
Select("s.*, (SELECT COUNT(*) FROM " + dao.secondTableName + " as l where s.id = l.secret_id) locks_total ")
var secretsTotal int64
var metadataResponseEntries []models.SecretMetadataResponse
txn = txn.Count(&secretsTotal). // Saving the count before trimming according to the pagination parameters
Limit(params.Limit).
Offset(params.Offset).
Order(constants.FieldName).
Order(constants.FieldId).
Find(&metadataResponseEntries)
When the SecretMetadataResponse contains the SecretMetadata which is the same fields as in the table and the LocksTotal is the new calculated field that we want to have.
type SecretMetadataResponse struct {
SecretMetadata
LocksTotal int `json:"locks_total"`
}
Thanks in advance :)
When using sql select I need a counter for my sequence row like this:
var result = from d in data
select new[]
{
Convert.ToString((count++))
};
but this syntax gives the following error message:
An expression tree may not contain an assignment operator Vehicle.app..NETCoreApp,Version=v1.0
When using LINQ (e.g. from x in data select { ... }) the expression in the selection is translated into a SQL statement and executed in the database. How would an assignment like count++ work in a database? I think you're better off with selecting the records from the database and apply the sequence number on the in memory list of data rather than on the queryable collection which represents the database. For example:
var data = (from d in data select new { ... }).ToList();
var result = data.Select(new { id = Convert.ToString(count++), ... }).ToList();
Good Day,
I am querying my database using Linq and I have run into a problem, the query searched a column for a search phrase and based on if the column has the phrase, it then returns the results, The query is below,
Dim pdb = New ProductDataContext()
Dim query =
From a In pdb.tblUSSeries
Join b In pdb.tblSizes_ On a.Series Equals b.Series
Where
a.Series.ToString().Equals(searchString) Or
b.Description.Contains(searchString) Or Not b.Description.Contains(Nothing)
Order By b.Series, b.OrderCode Ascending
Select New CustomSearch With
{
.Series = a.Series,
.SeriesDescription= a.Description,
.Coolant = a.Coolant,
.Material = a.Material,
.Standard = a.Standard,
.Surface = a.Surface,
.Type = a.Type,
.PointAngle = a.PointAngle,
.DiaRange = a.DiaRange,
.Shank = b.Shank,
.Flutes = b.Flutes,
.EDPNum = b.EDPNum,
.SizesDescription = b.Description,
.OrderCode = b.OrderCode
}
Return query
I think the problem is that, in the table certain rows are NULL, so when it is checking the column for the phrase and it encounters a row that is null it, breaks and returns this error,
The cast to value type 'System.Int32' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type.
I have ran this query against another column that has all the rows populated with data and it returns the results ok.
So my question is how can I write it in VB to query the db with the supplied searchstring and return the results, when some of the rows in the columns have null values.
Any help would be great.
The exception occurs when you make the projection (i.e. select new CustomSearch)
And yes your trying to assign Null to some int property
(Not sure which one of your properties that is)
one of 2 choices :
1) Use nullalbe types for your properties (or just that one property).
2) project with an inline If ( ?? in C#) , I don't know VB so don't catch me on the syntax.
Taking Series just as an example i don't know if it's an int or if that's the problematic property
Select New CustomSearch With
{
.Series = If(a.Series Is Nothing,0, CInt(a.Series))
}
In C#
Select new CustomSearch
{
Series = a.Series ?? 0;
}
Oracle DB.
Spring JPA using Hibernate.
I am having difficulty inserting a Clob value into a native sql query.
The code calling the query is as follows:
#SuppressWarnings("unchecked")
public List<Object[]> findQueryColumnsByNativeQuery(String queryString, Map<String, Object> namedParameters)
{
List<Object[]> result = null;
final Query query = em.createNativeQuery(queryString);
if (namedParameters != null)
{
Set<String> keys = namedParameters.keySet();
for (String key : keys)
{
final Object value = namedParameters.get(key);
query.setParameter(key, value);
}
}
query.setHint(QueryHints.HINT_READONLY, Boolean.TRUE);
result = query.getResultList();
return result;
}
The query string is of the format
SELECT COUNT ( DISTINCT ( <column> ) ) FROM <Table> c where (exact ( <column> , (:clobValue), null ) = 1 )
where "(exact ( , (:clobValue), null ) = 1 )" is a function and "clobValue" is a Clob.
I can adjust the query to work as follows:
SELECT COUNT ( DISTINCT ( <column> ) ) FROM <Table> c where (exact ( <column> , to_clob((:stringValue)), null ) = 1 )
where "stringValue" is a String but obviously this only works up to the max sql string size (4000) and I need to pass in much more than that.
I have tried to pass the Clob value as a java.sql.Clob using the method
final Clob clobValue = org.hibernate.engine.jdbc.ClobProxy.generateProxy(stringValue);
This results in a java.io.NotSerializableException: org.hibernate.engine.jdbc.ClobProxy
I have tried to Serialize the Clob using
final Clob clob = org.hibernate.engine.jdbc.ClobProxy.generateProxy(stringValue);
final Clob clobValue = SerializableClobProxy.generateProxy(clob);
But this appears to provide the wrong type of argument to the "exact" function resulting in (org.hibernate.engine.jdbc.spi.SqlExceptionHelper:144) - SQL Error: 29900, SQLState: 99999
(org.hibernate.engine.jdbc.spi.SqlExceptionHelper:146) - ORA-29900: operator binding does not exist
ORA-06553: PLS-306: wrong number or types of arguments in call to 'EXACT'
After reading some post about using Clobs with entities I have tried passing in a byte[] but this also provides the wrong argument type (org.hibernate.engine.jdbc.spi.SqlExceptionHelper:144) - SQL Error: 29900, SQLState: 99999
(org.hibernate.engine.jdbc.spi.SqlExceptionHelper:146) - ORA-29900: operator binding does not exist
ORA-06553: PLS-306: wrong number or types of arguments in call to 'EXACT'
I can also just pass in the value as a String as long as it doesn't break the max string value
I have seen a post (Using function in where clause with clob parameter) which seems to suggest that the only way is to use "plain old JDBC". This is not an option.
I am up against a hard deadline so any help is very welcome.
I'm afraid your assumptions about CLOBs in Oracle are wrong. In Oracle CLOB locator is something like a file handle. And such handle can be created by the database only. So you can not simply pass CLOB as bind variable. CLOB must be somehow related to database storage, because this it can occupy up to 176TB and something like that can not be held in Java Heap.
So the usual approach is to call either DB functions empty_clob() or dbms_lob.create_temporary (in some form). Then you get a clob from database even if you think it is "IN" parameter. Then you can write as many data as you want into that locator (handle, CLOB) and then you can use this CLOB as a parameter for a query.
If you do not follow this pattern, your code will not work. It does not matter whether you use JPA, SpringBatch or plan JDBC. This constrain is given by the database.
It seems that it's required to set type of parameter explicitly for Hibernate in such cases. The following code worked for me:
Clob clob = entityManager
.unwrap(Session.class)
.getLobHelper()
.createClob(reader, length);
int inserted = entityManager
.unwrap(org.hibernate.Session.class)
.createSQLQuery("INSERT INTO EXAMPLE ( UUID, TYPE, DATA) VALUES (:uuid, :type, :data)")
.setParameter("uuid", java.util.Uuid.randomUUID(), org.hibernate.type.UUIDBinaryType.INSTANCE)
.setParameter("type", java.util.Uuid.randomUUID(), org.hibernate.type.StringType.INSTANCE)
.setParameter("data", clob, org.hibernate.type.ClobType.INSTANCE)
.executeUpdate();
Similar workaround is available for Blob.
THE ANSWER: Thank you both for your answers. I should have updated this when i solved the issue some time ago. In the end I used JDBC and the problem disappeared in a puff of smoke!
I have a wrapped fluent nhibernate framework that I'm reusing and have no control over the actual mapping.
In my entity object I have a property mapped as string to an XML column in sql.
Hence when I run a query like:
var myResult = (from myTable in DataManager.Session.Query<Table>()
where myTable.thatXmlFieldWhichIsMappedAsString.Contains(AnXmlSnippet))
select myTable).FirstOrDefault();
It is trying to use the LIKE operator in SQL which is invalid on that column type.
How can I get around this without having to select all the rows and converting to List first?
In case, that we do not need .Query() (LINQ), and we can use Criteria query or QueryOver, we can use conversion:
// the projection of the column with xml
// casted to nvarchar
var projection = Projections
.Cast(NHibernateUtil.StringClob
, Projections.Property("thatXmlFieldWhichIsMappedAsString"));
// criteria filtering with LIKE
var criteria = Restrictions.Like(projection, "searched xml");
// query and result
var query = session.QueryOver<MyEntity>()
.Where(criteria)
;
var result = query
.SingleOrDefault<MyEntity>()
;
From my experience this could lead to conversion into small nvarchar(255) - sql server... Then we can do it like this:
var projection = Projections
.SqlProjection("CAST(thatXmlFieldWhichIsMappedAsString as nvarchar(max)) AS str"
, new string[]{}
, new NHibernate.Type.IType[]{}
);