UCanAccess allows ambigious column names - ucanaccess

It appears that UCanAccess does not complain when a column name appearing in the SELECT clause, WHERE clause, etc. is ambiguous. Instead, it seems that the first table in the FROM clause that has a column with that name is used. This is a very dangerous behaviour that most other database engines reject. For example Access will respond with an error message "The Specified field 'something' could refer to more than one table listed in the FROM clause of your SQL statement". Similarly SQL Server would complain with the message "Ambiguous column name 'something'". MySQL complains with the message "Column 'something' in field list is ambiguous". DB2 responds "‪A‬‎ ‪reference‬‎ ‪to‬‎ ‪column‬‎ ‪‬‎"‪something"‬‎ ‪is‬‎ ‪ambiguous‬‎". And Oracle responds "column ambiguously defined".
Is it possible to fix this in UCanAccess? Is there a way to configure this behaviour?

Related

Oracle PSQL getting reason of error in a with as expression

I have a more thousand lines "with as" sql. When I try to run it I've got a message:
"Expression must have same datatype as corresponding expression", but I cannot get any info where is it and which field is not the same type. In a normal sql I can get it, but in with as I cannot. Yes I know "with as" is not the best practice, but I have to port an old sql to a new environment.
Is there any trick to get where is it?

Oracle Alter command to rename existing Column errorring

alter table tablename rename column zl_divn_nbr to div_loc_nbr;
Error while executing the above statement. Please help.
SQL Error: ORA-54032: column to be renamed is used in a virtual column expression
54032. 0000 - "column to be renamed is used in a virtual column expression"
*Cause: Attempted to rename a column that was used in a virtual column
expression.
*Action: Drop the virtual column first or change the virtual column
expression to eliminate dependency on the column to be renamed
Run the following SQL query in your database using the table name mentioned in the error message. For example, in the error message shown in this article, the table name is 'tablename'. Note that whilst the table name appears in lower case in the error message, it may be upper case in your DB. This query is case sensitive so if you receive no results, check whether the table name is upper case inside your database.
SELECT COLUMN_NAME, DATA_DEFAULT, HIDDEN_COLUMN
FROM USER_TAB_COLS
WHERE TABLE_NAME = 'tablename';
Before proceeding, make sure the Bitbucket Server process is not running. If Extended Statistics has been enabled, contact your database administrator to have them drop the Extended Statistics metadata from the table, and proceed with your upgrade. If you wish to enable Extended Statistics again after the upgrade you may do so, however be aware that you may need to repeat this process again for subsequent upgrades otherwise you risk running into this issue again.
Removing columns created by Extended Statistics requires using an in-build stored procedure,
DBMS_STATS.DROP_EXTENDED_STATS().
Usage of this stored procedure is covered further in ORA-54033 and the Hidden Virtual Column Mystery, and looks similar to the following:
EXEC DBMS_STATS.DROP_EXTENDED_STATS(ownname=>'<YOUR_DB_USERNAME>', tabname=>'tablename', extension=>'("PR_ROLE", "USER_ID", "PR_APPROVED")')
References
Database Upgrade Eror: column to be rename
Thanks.
Probably, you have such a table :
CREATE TABLE tablename(
id NUMBER,
zl_divn_nbr NUMBER,
zl_divn_percent NUMBER GENERATED ALWAYS AS (ROUND(zl_divn_nbr/100,2)) VIRTUAL
);
where zl_divn_nbr column is used for a computation for virtual(zl_divn_percent) column.
To rename zl_divn_nbr, all referenced virtual columns to this column should be removed, and may be created later.
The syntax for defining a virtual column is this :
column_name [datatype] [GENERATED ALWAYS] AS (expression) [VIRTUAL]
Since version 11 R1, we have this property.
ALTER TABLE rename column to
In the case of tables with virtual or 'group extension columns' the above
statement returns an error before Oracle 12cR2. For Oracle 12cR2 or newer versions the above statement runs fine cause 'renaming column' command is decoupled from the group extension aspect.

JDBC Error in insert with DB2 (works with Sql Server)

I use in a Java Application JDBC to query the DBMS. The application works correctly with Sql Server but I get this error in DB2 during one insert:
com.ibm.db2.jcc.am.SqlDataException: DB2 SQL Error: SQLCODE=-302, SQLSTATE=22001, SQLERRMC=1, DRIVER=3.63.75
The insert is made using the ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE.
My query is a plain select of the table, then I declare my PreparedStatement, passing the parameters and afterwards with the ResultSet I do first the moveToInsertRow() and then the insertRow().
Do you know if there are any problems with this approach using DB2?
As I told you before the same code works correctly with Sql Server.
SQL Code -302 on DB2 means:
THE VALUE OF INPUT VARIABLE OR PARAMETER NUMBER position-number IS INVALID OR TOO LARGE FOR THE TARGET COLUMN OR THE TARGET VALUE
So it seems like you are trying to insert a value into a column which is too large or too short (e.g. Hello World into a varchar(5)). Probably the column has a different length in DB2 and sql-server or you are inserting different values.
Probably too late to add to this thread.. but someone else might find it useful
Got the same SQL Exception when trying to do a SELECT : didn't realize the property value in WHERE clause was exceeding the limit on the corresponding column
SELECT * FROM <schema>.<table_name> WHERE PropertyName = 'value';
value was a VARCHAR type but exceeded the Length limit
Detailed exception does say it clearly that data integrity was violated: org.springframework.dao.DataIntegrityViolationException
So a good idea would be to do a length check on the value(s) that are being set on the properties before firing any queries to the database.

Run a Query from Linked Server (Oracle) in SQL Server2008 R2

I have the linked server set up in SQL Server 2008. But I could not run any query against the linked server.
I tried to run this simple command but it's not working
SELECT * FROM MYSERVER..ALANH.TEMP_UPDATE1
This is the error I got when I run the above command.
Msg 7399, Level 16, State 1, Line 1
The OLE DB provider "OraOLEDB.Oracle" for linked server "MYSERVER" reported an error. The provider did not give any information about the error.
Msg 7312, Level 16, State 1, Line 1
Invalid use of schema or catalog for OLE DB provider "OraOLEDB.Oracle" for linked server "MYSERVER". A four-part name was supplied, but the provider does not expose the necessary interfaces to use a catalog or schema.
Could anyone help me to connect to the OracleLinkedServer? Thanks very much.
you can be that way too:
**SELECT * FROM OPENQUERY(MYSERVER, 'SELECT * FROM ALANH.TEMP_UPDATE1')**
You can write the query like this:
select * FROM [MYSERVER]..[ALANH].[TEMP_UPDATE1]
Important: In this case, the fully qualified table name must be written in upper case.
You might try the fix from this article.
Also, this could be a problem with naming. From an MS KB article
If you receive these error messages, a table may be missing in the
Oracle schema or you may not have permissions on that table. Verify
that the schema name has been typed by using uppercase. The
alphabetical case of the table and of the columns should be as
specified in the Oracle system tables.
On the Oracle side, a table or a column that is created without double
quotation marks is stored in uppercase. If the table or the column is
enclosed in double quotation marks, the table or the column is stored
as is.
First make sure the tnsping utility works from client server, then use the below string in linked server database source setup
host[:port]/service_name
Check this link for more details :
http://www.oracledistilled.com/oracle-database/oracle-net/using-easy-connect-ezconnect-naming-method-to-connect-to-oracle-databases/
Try something like this:
SELECT * FROM ALL_TABLES#"SOME.SERVER.NAME";
In this case I'm selecting ALL_TABLES from a linked server called SOME.SERVER.NAME.
Richard's post above was critical.
I am using v12 ODP.NET odbc drivers and had to ensure that "Zero Level Only" was NOT checked and that the names supplied for table and schema were the correct case. All of the schemas and tables I access are uppercase only.
Use the query below to determine what the correct table name is, though you will have to supply the schema name in the correct case for the query to work. Try all uppercase, try all lowercase, try mixed case, or better yet get the actual name from the dba (I've heard that only table/schema names that are "" quoted will be allowed mixed case, otherwise in oracle it's all uppercase.)
sp_tables_ex #table_server=InsertLinkedServerHere, #table_schema=InsertSchemaNameHere

ORA-12704: Unable to convert character data

I am trying to perform SET operations in Oracle across remote databases.
I am using the MINUS operator.
My query looks something like this.
SELECT NAME FROM localdb MINUS SELECT NAME from remotedb#dblink
This is throwing up a ORA-12704 error. I understand this warrants some kind of conversion or a NLS Setting.
What should I try next?
The two name columns are stored in different characters sets. This could be because of their type definitions, or it could be because the two databases are using different character sets.
You might be able to get around this by explicitly converting the field from the remote database to the character set of the local one. Try this:
SELECT NAME FROM localdb MINUS SELECT TO_CHAR(NAME) from remotedb#dblink
It seams the types of NAME column in those 2 tables are different.
Make sure the NAME column in the remotedb table is exactly the same type as the NAME in localdb table. It is mandatory when you use a MINUS operator.

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