From the Unity JDBC download page:
If the SQL query requires joins or functions not supported by MongoDB, then the query is promoted to UnityJDBC (trial version). The UnityJDBC trial version has no expiration date and is fully functioning except that it is limited to returning up to 100 results.
However, when I try to join two tables using any syntax like
SELECT * from a, b WHERE a.id = b.id
SELECT * from a INNER JOIN b ON a.id = b.id
SELECT * from a INNER JOIN b USING (id)
Results in the following:
Exception: java.sql.SQLException: ERROR: No schema defined. The default schema location is _schema in the current database. You need write permission to create this collection. Otherwise, use the schema parameter to set a file location (e.g. schema=mongo.xml) to store the schema. See connection parameters at http://www.unityjdbc.com/mongojdbc/ for more details.
java.sql.SQLException: ERROR: No schema defined. The default schema location is _schema in the current database. You need write permission to create this collection. Otherwise, use the schema parameter to set a file location (e.g. schema=mongo.xml) to store the schema. See connection parameters at http://www.unityjdbc.com/mongojdbc/ for more details.
at mongodb.conn.ServerConnection.processMongoWithUnity(Unknown Source)
at mongodb.conn.ServerConnection.executeQuery(Unknown Source)
at mongodb.jdbc.MongoStatement.executeQuery(Unknown Source)
at mongodb.ExampleMongoJDBC.doQuery(ExampleMongoJDBC.java:222)
at mongodb.ExampleMongoJDBC.main(ExampleMongoJDBC.java:66)
Ok, so I took a look in the readme and found it mentioning the code/test/dspec/ folder with some files related to schemas. I opened a few up, they are highly detailed xml files of all the collections mapping them to relational data types.
Do I have to write one of these out, or is there a way to auto generate it?
I received a (fast) response from the Unity team.
The MongoDB JDBC driver has two modes. For single collection queries, it does not build a schema. For queries involving joins or expressions it builds a schema and by default stores it in the _schema collection in the current Mongo database. If you do not have permission to write to the database, an error is thrown.
As mentioned in the error, you can set the schema parameter to be a local file name (such as mongo.xml) and it will store it on your computer rather than in the Mongo database. You could also use an account that has write permissions.
To make this work, add schema=mongo.xml to your connection URL like this:
jdbc:mongo://localhost/dbname?schema=mongo.xml?rebuildschema=true
After this is done the first time, you can remove the rebuildschema=true or it will rebuild it every time.
The only thing I'm confused about is that I'm using a database which doesn't require authentication. I even made a user with write permissions, connected to him, and still received the above error.
--EDIT
I realized that you could also just do jdbc:mongo://localhost/dbname?rebuildschema=true. If the schema hasn't been created, then the previous error will be thrown.
Related
I'm using the Impala JDBC driver (or I guess it's actually the Hive Server 2 JDBC driver). I have a view created in another database -- let's call it "store55".
Let's say my view is defined as follows:
CREATE VIEW good_customers AS
SELECT * from customers WHERE good = true;
When I try to query this view using JDBC as follow:
SELECT * FROM store55.good_customers LIMIT 10
I get an error such as:
java.sql.SQLException: AnalysisException: Table does not exist: default.customers
Ideally, I'd like to specify the database name somewhere in the JDBC URL or as a parameter but when I try to use this JDBC url, I still get the same error:
jdbc:hive2://<host>:<port>/store55;auth=noSasl
Doe the Hive2 JDBC driver just ignore the database part of the URL and assume all queries are executed against the default database?
The only way I was able to have the queries return is to change the view definition itself to include the database name:
CREATE VIEW good_customers AS
SELECT * from store55.customers WHERE good = true;
However, I'd like to keep the view definition free of database names.
Thanks!
You might want to specify in JDBC the "use database xxxxx;" statement.
Also, if you are already using the database try "invalidate metadata" statement.
The URL is jdbc:hive2://:/store55;auth=noSasl correct
Can you run few diagnostics such as:
SHOW TABLES - to ensure that the view is created in store55
Are you using the USE DATABASE command in the DDL's
I'm attempting to run a simple statement against an Access DB to find records.
Data validation in the records was horrible, and I cannot sanitize it. Meaning, it must be preserved as is.
I need to be able to search against a string with white space and hyphen characters removed. The following statement will work in Access 2010 direct:
select * from dummy where Replace(Replace([data1],' ',''),'-','') = 'ABCD1234';
Running it from an ODBC connection via PHP will not. It produces the following error:
SQL error: [Microsoft][ODBC Microsoft Access Driver] Undefined function 'Replace' in expression., SQL state 37000 in SQLExecDirect
Creating a query in the database that runs the function and attempting to search its values indirectly causes the same error:
select * from dummy_indirect where Expr1 = 'ABCD1234';
I've attempted to use both ODBC drivers present. ODBCJR32.dll (03/22/2010) and ACEODBC.dll (02/18/2007). To my knowledge these should be current as it was installed with the full Access 2010 and Access 2010 Database Engine.
Any ideas on how to work around this error and achieve the same effect are welcome. Please note, that I cannot alter the database in way, shape, or form. That indirect query was created in another mdb file that has the original tables linked from the original DB.
* Update *
OleDB did not really affect anything.
$dsn= "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\dummy.mdb;";
I'm not attempting to use it as a web backend either. I'm not a sadomasochist.
There is a legacy system that I must support that does use Access as a backend. Data gets populated there from other old systems that I must integrate into more modern systems. Hence, the creation of an API with Apache/PHP that is running on the server supporting the legacy system.
I need to be able to search a table that has an alphanumeric case identifier to get a numeric identifier that is unique and tied to a generator (Autonumber in access). Users have been using it a trash box for years (inconsistent data entry with sporadic notations) so the only solution I have is to strip everything except alphanumeric out of both the field value and the search value and attempt to perform a LIKE comparison against it.
If not replace() which is access supported, what ODBC compatible functions exist that I can use do the same kind of comparison?
Just to recap, the Access db engine will not recognize the Replace() function unless your query is run from within an Access application session. Any attempt from outside Access will trigger that "Undefined function" error message. You can't avoid the error by switching from ODBC to OleDb as the connection method. And you also can't trick the engine into using Replace() by hiding it in separate query (in the same or another Access db) and using that query as the data source for your main query.
This behavior is determined by Access' sandbox mode. That linked page includes a list of functions which are available in the default sandbox mode. That page also describes how you can alter the sandbox mode. If you absolutely must have Replace() available for your query, perhaps the lowest setting (0) would allow it. However, I'm not recommending you do that. I've never done it myself, so don't know anything about the consequences.
As for alternatives for Replace(), it would help to know about the variability in the values you're searching. If the space or dash characters appear in only one or a few consistent positions, you could do a pattern match with a Like expression. For example, if the search field values consist of 4 letters, an optional space or dash, followed by 4 digits, a WHERE clause like this should work for the variations of "ABCD1234":
SELECT * FROM dummy
WHERE
data1 = 'ABCD1234'
OR data1 Like 'ABCD[- ]1234';
Another possibility is to compare against a list of values:
SELECT * FROM dummy
WHERE
data1 IN ('ABCD1234','ABCD 1234','ABCD-1234');
However if your search field values can include any number of spaces or dashes at any position within the string, that approach is no good. And I would look real hard for some way to make the query task easier:
You can't clean the stored values because you're prohibited from altering the original Access db in any way. Perhaps you could create a new Access db, import the data, and clean that instead.
Set up the original Access db as a linked server in SQL Server and build your query to take advantage of SQL Server features.
Surrender. :-( Pull in a larger data set to your PHP client code, and evaluate which rows to use vs. which to ignore.
I'm not sure you can do this with ODBC and your constraints. The MS Access driver is limited (by design; MS wants you to use SQL Server for back ends).
Can you use OLEDB? that might be an option.
I'm looking for a way to programmatically execute arbitrary SQL commands against my DB.
(Hibernate, JPA, HSQL)
Query.createNativeQuery() doesn't work for things like CREATE TABLE.
Doing LOTS of searching, I thought I could use the Hibernate Session.doWork().
By using the deprecated Configuration.buildSesionFactory() seems to show that doWork won't work.
I get "use lacks privilege or object not found" for all the CREATE TABLE statements.
So, what other technique is there for executing arbitratry SQL statements?
There were some notes on using the underlying JDBC Statement, but I haven't figure out how to get a JDBC Connection object from Hibernate to try that.
Note that the hibernate.hbm2ddl.auto=create setting will NOT work for me, as I have ARRAY[] columns which it chokes on.
I don't think there is any problem executing a create table statement with a Hibernate native query. Just make sure to use Query.executeUpdate(), and not Query.list() or Query.uniqueResult().
If it doesn't work, please tell us what happens when you execute it, and join the full stack trace of the exception and the SQL query you're executing.
"use lacks privilege or object not found" in HSQL may mean anything, for example existence of a table with the same name. Error messages in HSQL are completely misleading. Try listing your tables using DatabaseMetadata - you have probably already created the table.
I've hit a bit of an impasse. I have a query that is generated by some C# code. The query works fine in Microsoft SQL Server Management Studio when run against the same database.
However when my code tries to run the same query I get the same error about an invalid column and an exception is thrown. All queries that reference this column are failing.
The column in question was recently added to the database. It is a date column called Incident_Begin_Time_ts .
An example that fails is:
select * from PerfDiag
where Incident_Begin_Time_ts > '2010-01-01 00:00:00';
Other queries like Select MAX(Incident_Being_Time_ts); also fail when run in code because it thinks the column is missing.
Any ideas?
Just press Ctrl + Shift + R and see...
In SQL Server Management Studio, Ctrl+Shift+R refreshes the local cache.
I suspect that you have two tables with the same name. One is owned by the schema 'dbo' (dbo.PerfDiag), and the other is owned by the default schema of the account used to connect to SQL Server (something like userid.PerfDiag).
When you have an unqualified reference to a schema object (such as a table) — one not qualified by schema name — the object reference must be resolved. Name resolution occurs by searching in the following sequence for an object of the appropriate type (table) with the specified name. The name resolves to the first match:
Under the default schema of the user.
Under the schema 'dbo'.
The unqualified reference is bound to the first match in the above sequence.
As a general recommended practice, one should always qualify references to schema objects, for performance reasons:
An unqualified reference may invalidate a cached execution plan for the stored procedure or query, since the schema to which the reference was bound may change depending on the credentials executing the stored procedure or query. This results in recompilation of the query/stored procedure, a performance hit. Recompilations cause compile locks to be taken out, blocking others from accessing the needed resource(s).
Name resolution slows down query execution as two probes must be made to resolve to the likely version of the object (that owned by 'dbo'). This is the usual case. The only time a single probe will resolve the name is if the current user owns an object of the specified name and type.
[Edited to further note]
The other possibilities are (in no particular order):
You aren't connected to the database you think you are.
You aren't connected to the SQL Server instance you think you are.
Double check your connect strings and ensure that they explicitly specify the SQL Server instance name and the database name.
In my case I restart Microsoft SQL Sever Management Studio and this works well for me.
If you are running this inside a transaction and a SQL statement before this drops/alters the table you can also get this message.
I eventually shut-down and restarted Microsoft SQL Server Management Studio; and that fixed it for me. But at other times, just starting a new query window was enough.
If you are using variables with the same name as your column, it could be that you forgot the '#' variable marker. In an INSERT statement it will be detected as a column.
Just had the exact same problem. I renamed some aliased columns in a temporary table which is further used by another part of the same code. For some reason, this was not captured by SQL Server Management Studio and it complained about invalid column names.
What I simply did is create a new query, copy paste the SQL code from the old query to this new query and run it again. This seemed to refresh the environment correctly.
In my case I was trying to get the value from wrong ResultSet when querying multiple SQL statements.
In my case it seems the problem was a weird caching problem. The solutions above didn't work.
If your code was working fine and you added a column to one of your tables and it gives the 'invalid column name' error, and the solutions above doesn't work, try this: First run only the section of code for creating that modified table and then run the whole code.
Including this answer because this was the top result for "invalid column name sql" on google and I didn't see this answer here. In my case, I was getting Invalid Column Name, Id1 because I had used the wrong id in my .HasForeignKey statement in my Entity Framework C# code. Once I changed it to match the .HasOne() object's id, the error was gone.
I've gotten this error when running a scalar function using a table value, but the Select statement in my scalar function RETURN clause was missing the "FROM table" portion. :facepalms:
Also happens when you forget to change the ConnectionString and ask a table that has no idea about the changes you're making locally.
I had this problem with a View, but the exact same SQL code worked perfectly as a query. In fact SSMS actually threw up a couple of other problems with the View, that it did not have with the query. I tried refreshing, closing the connection to the server and going back in, and renaming columns - nothing worked. Instead I created the query as a stored procedure, and connected Excel to that rather than the View, and this solved the problem.
This may be a dumb question. But I just received permissions to read/write to this DB. I see the tables of the DB, except for one. I can select from it, But I cannot see it in the Object Explorer. I restarted my computer, refreshed the object explorer and everything. Is there a restriction on viewing this table?
I"m so sorry I had to check the connection of the query. I was looking at two different versions of the same DATABASE. gosh. Should I take this question down?
The query
SELECT type, type_desc FROM sys.objects WHERE name = 'my_table_name'
should tell you what type of object your table really is.
Could it be a synonym, or a view? Check under the synonyms node and the views node. Also check the schema... if you are just saying SELECT * FROM table, try with SELECT * FROM dbo.table. It may be under a different schema.
You need to use the schema name in your create table query(eg. dbo.table name). By default it is getting created under your local server and hence it is available for you when you use the select query but once you check on server ita is not available.
When all else fails, right click on Tables and click Refresh.