I have the following piece of XML:
<per:Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.something.com/2014/11/bla/webservice.xsd"
xmlns:per="http://www.something.com/2014/11/bla/person">
<per:Initials>E.C.</per:Initials>
<per:FirstName>Erik</per:FirstName>
<per:LastName>Flipsen</per:LastName>
<per:BirthDate>1980-07-01</per:BirthDate>
<per:Gender>Male</per:Gender>
</per:Person>
From this xml I want to extract some data in PL/SQL. I'd like to use XMLTABLE, since the EXTRACT and EXTRACTVALUE functions are deprecated.
I am able to extract the data using this query:
select pers.Initials,
pers.Firstname
into lsInitials,
lsFirstname
from
XMLTABLE ('*:Person' passing pxRequest
columns Initials PATH '*:Initials',
Firstname PATH '*:FirstName'
) pers;
I'm using wildcards for the namespaces since I don't really care what abbreviations the sending party is using for the namespace, I know the exact path where to get my data anyway.
With this code I have two things that puzzle me:
According to the documentation on http://docs.oracle.com/database/121/SQLRF/functions268.htm#SQLRF06232 PATH should be optional, however, as soon as I remove the PATH from the COLUMNS section, I don't get any results anymore.
Edit:
I found out that when I remove the namespaces for the elements, and made them uppercase, it works. So it seems like the column names need to match the xml elements names to make it work. I didn't yet figure out how to make it work with namespaced XML.
The documentation also notes "For each resulting column except the FOR ORDINALITY column, you must specify the column data type", however, it seems to work fine without it. It also seems a bit redundant to specify it for the columns and for the variables I'm fetching the data into. Any idea if not specifying the data types could get me into trouble?
Runnable code sample:
SET SERVEROUTPUT ON;
DECLARE
pxRequest xmltype := xmltype('<per:Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.something.com/2014/11/bla/webservice.xsd"
xmlns:per="http://www.something.com/2014/11/bla/person">
<per:Initials>E.C.</per:Initials>
<per:FirstName>Erik</per:FirstName>
<per:LastName>Flipsen</per:LastName>
<per:BirthDate>1980-01-01</per:BirthDate>
<per:Gender>Male</per:Gender>
</per:Person>');
lsInitials varchar2(100);
lsFirstname varchar2(100);
begin
select pers.Initials,
pers.Firstname
into lsInitials,
lsFirstname
from
XMLTABLE ('*:Person' passing pxRequest
columns Initials PATH '*:Initials',
Firstname PATH '*:FirstName'
) pers;
dbms_output.put_line(lsInitials);
dbms_output.put_line(lsFirstname);
end;
As per your first question, the documentation you linked has this to day about omitting PATH:
The optional PATH clause specifies that the portion of the XQuery result that is addressed by XQuery expression string is to be used as the column content.
If you omit PATH, then the XQuery expression column is assumed. For example:
(... COLUMNS xyz)
is equivalent to
XMLTable(... COLUMNS xyz PATH 'XYZ')
You can use different PATH clauses to split the XQuery result into different virtual-table columns.
The reason the column xyz is assumed to be 'XYZ' is because Oracle, by default, is case insensitive (defaults to all-caps). If you had defined your column as "aBcD" then the PATH value will be assumed to be 'aBcD'
As for your second question about specifying data types: if the data you're extracting is always going to be text data, you might be able to get away with not specifying a data type.
However, if you start dealing with things like dates, timestamps, floating point numbers, etc, then you may run into issues. You'll either need to manually convert them using the TO_* functions or you can specify their data types in the column definitions. If you don't, Oracle is free to implicitly cast it however it feels fit, which may have unexpected consequences.
References:
https://stackoverflow.com/a/9976068/377141
How to parse xml by xmltable when using namespace in xml(Oracle)
It should work as expected if you load in the namespace elements in your xmltable:
select results
from xmltable(
xmlnamespaces(
default 'http://tempuri.org/',
'http://schemas.xmlsoap.org/soap/envelope/' as "soap"
),
'soap:Envelope/soap:Body/addResponse' passing xmltype(v_xml)
columns results varchar(100) path './addResult')
From your example (you may also need to register your schema/namespace ahead of time, but that should be once):
select pers.Initials,
pers.Firstname
into lsInitials,
lsFirstname
from
XMLTABLE (
xmlnamespaces(
default 'http://tempuri.org/',
'http://www.w3.org/2001/XMLSchema-instance' as "xsi",
'http://www.something.com/2014/11/bla/person' as "per"
),
passing pxRequest
columns Initials PATH '*:Initials',
Firstname PATH '*:FirstName'
) pers;
Things that used to work in previous versions of Oracle do not work in 11g+ with respect to XML, as from what I have seen, Oracle strongly verifies/types the input/output of XML operations where in previous versions you could run normal proper XQuery operations without namespace info.
Related
Beginner in SQL i'm currently unable to run this insert basic command.
insert into Project(ProjId,MedicName,Purpose,Start_date,End_date,PI_Id)
insert into Project values('PR003','Medic3','lung','01-Nov-14','31-DEC-20','10101');
ERROR at line 2:
ORA-00926: missing VALUES keyword
Your syntax is wrong. You need to write one statement:
insert into Project(ProjId,MedicName,Purpose,Start_date,End_date,PI_Id)
values('PR003','Medic3','lung','01-Nov-14','31-DEC-20','10101');
Apart from the wrong syntax (you've already been told that), as it appears that certain columns in that table are DATE datatype, I'd suggest you not to enter strings into it, but dates. Becuase, both '01-Nov-14' and '31-DEC-20' are strings.
Don't rely on Oracle's implicit conversion. As long as it might work now, it'll fail sooner or later (when NLS settings change) not necessarily on this database, but on some other. For example, your values wouldn't fit into my database because my format is different, as well as language (we don't use English names). Take control over it.
You could
use date literal (which I used for start_date)
use TO_DATE function with appropriate format mask (end_date below)
Something like this:
INSERT INTO project (projid,
medicname,
purpose,
start_date,
end_date,
pi_id)
VALUES ('PR003',
'Medic3',
'lung',
DATE '2014-11-01', --> this
TO_DATE('31.12.2020', 'dd.mm.yyyy'), --> this
'10101');
One of my columns is called from. I can't change the name because I didn't make it.
Am I allowed to do something like SELECT from FROM TableName or is there a special syntax to avoid the SQL Server being confused?
Wrap the column name in brackets like so, from becomes [from].
select [from] from table;
It is also possible to use the following (useful when querying multiple tables):
select table.[from] from table;
If it had been in PostgreSQL, use double quotes around the name, like:
select "from" from "table";
Note: Internally PostgreSQL automatically converts all unquoted commands and parameters to lower case. That have the effect that commands and identifiers aren't case sensitive. sEleCt * from tAblE; is interpreted as select * from table;. However, parameters inside double quotes are used as is, and therefore ARE case sensitive: select * from "table"; and select * from "Table"; gets the result from two different tables.
These are the two ways to do it:
Use back quote as here:
SELECT `from` FROM TableName
You can mention with table name as:
SELECT TableName.from FROM TableName
While you are doing it - alias it as something else (or better yet, use a view or an SP and deprecate the old direct access method).
SELECT [from] AS TransferFrom -- Or something else more suitable
FROM TableName
Your question seems to be well answered here, but I just want to add one more comment to this subject.
Those designing the database should be well aware of the reserved keywords and avoid using them. If you discover someone using it, inform them about it (in a polite way). The keyword here is reserved word.
More information:
"Reserved keywords should not be used
as object names. Databases upgraded
from earlier versions of SQL Server
may contain identifiers that include
words not reserved in the earlier
version, but that are reserved words
for the current version of SQL Server.
You can refer to the object by using
delimited identifiers until the name
can be changed."
http://msdn.microsoft.com/en-us/library/ms176027.aspx
and
"If your database does contain names
that match reserved keywords, you must
use delimited identifiers when you
refer to those objects. For more
information, see Identifiers (DMX)."
http://msdn.microsoft.com/en-us/library/ms132178.aspx
In Apache Drill, use backquotes:
select `from` from table;
If you ARE using SQL Server, you can just simply wrap the square brackets around the column or table name.
select [select]
from [table]
I have also faced this issue.
And the solution for this is to put [Column_Name] like this in the query.
string query= "Select [Name],[Email] from Person";
So it will work perfectly well.
Hi I work on Teradata systems that is completely ANSI compliant. Use double quotes " " to name such columns.
E.g. type is a SQL reserved keyword, and when used within quotes, type is treated as a user specified name.
See below code example:
CREATE TABLE alpha1
AS
(
SEL
product1
type_of_product AS "type"
FROM beta1
) WITH DATA
PRIMARY INDEX (product1)
--type is a SQL reserved keyword
TYPE
--see? now to retrieve the column you would use:
SEL "type" FROM alpha1
I ran in the same issue when trying to update a column which name was a keyword. The solution above didn't help me. I solved it out by simply specifying the name of the table like this:
UPDATE `survey`
SET survey.values='yes,no'
WHERE (question='Did you agree?')
The following will work perfectly:
SELECT DISTINCT table.from AS a FROM table
Some solid answers—but the most-upvoted one is parochial, only dealing with SQL Server. In summary:
If you have source control, the best solution is to stick to the rules, and avoid using reserved words. This list has been around for ages, and covers most of the peculiarities. One tip is that reserved words are rarely plural—so you're usually safe using plural names. Exceptions are DIAGNOSTICS, SCHEMAS, OCTETS, OFFSETS, OPTIONS, VALUES, PARAMETERS, PRIVILEGES and also verb-like words that also appear plural: OVERLAPS, READS, RETURNS, TRANSFORMS.
Many of us don't have the luxury of changing the field names. There, you'll need to know the details of the RDBM you're accessing:
For SQL Server use [square_braces] around the name. This works in an ODBC connection too.
For MySQL use `back_ticks`.
Postgres, Oracle and several other RDBMs will apparently allow "double_quotes" to be used.
Dotting the offending word onto the table name may also work.
You can put your column name in bracket like:
Select [from] from < ur_tablename>
Or
Put in a temprary table then use as you like.
Example:
Declare #temp_table table(temp_from varchar(max))
Insert into #temp_table
Select * from your_tablename
Here I just assume that your_tablename contains only one column (i.e. from).
In MySQL, alternatively to using back quotes (`), you can use the UI to alter column names. Right click the table > Alter table > Edit the column name that contains sql keyword > Commit.
select [from] from <table>
As a note, the above does not work in MySQL
Judging from the answers here and my own experience. The only acceptable answer, if you're planning on being portable is don't use SQL keywords for table, column, or other names.
All these answers work in the various databases but apparently a lot don't support the ANSI solution.
Simple solution
Lets say the column name is from ; So the column name in query can be referred by table alias
Select * from user u where u.from="US"
In Oracle SQL Developer, pl/sql you can do this with double quotes but if you use double quotes you must type the column names in upper case. For example, SELECT "FROM" FROM MY_TABLE
I have an insert statement, where one of the inserted fields is date. I use to_date function to convert string to date in this way:
to_date('10-MAY-10', 'DD-MON-RR')
It works fine, but I found, that it allows also variants like:
to_date('10?MAY?10', 'DD-MON-RR')
to_date('10+MAY+10', 'DD-MON-RR')
I'm expecting an Oracle error, however it makes an insert. Could you please explain why or give a reference to relevant documentation?
Oracle will test for other formats if it fails to find a match in the string - you can see the rules for what it looks for here in the documentation.
As an aside, years have four digits. Please make sure you specify all four when you provide a date-as-a-string, where possible; it saves the database from having to guess and potentially getting it wrong. I.e. your original example should be:
to_date('10-05-2010', 'DD-MM-YYYY')
If you need to restrict the date-as-a-string to a specific format, you can use the fx format modifier, which is mentioned earlier in the same document I linked to previously.
eg. to_date('10/05/2010', 'dd-mm-yyyy') would match but to_date('10/05/2010', 'fxdd-mm-yyyy') would fail
From what I can tell, there are only two types of results the Go database/sql interface library expects back - a row or an array of rows. However, there is at least one more type of result - a single column.
DB.column('SELECT COUNT(*) FROM `user` WHERE `banned` IS NOT NULL')
Is there any way to handle this - or do I just have to fetch a row and then access the COUNT(*) from that?
Yes you fetch a one column row but is that so hard ?
var count int
row := db.QueryRow("SELECT COUNT(*) FROM `user` WHERE `banned` IS NOT NULL")
err := row.Scan(&count)
Note that this may be compacted if you find it too verbose (you may remove the row variable).
I think that other similar systems in other languages (for example JDBC) don't offer natively this shortcut either.
I find easier to handle an API that I can memorize and browse rather than an API which has all the utilities I might be willing to use to remove one line in my code.
For the record, a SQL Server stored procedure returns all of the following (at the same time):
an integer return code
zero or more messages (often warnings or errors) containing text and two integer codes
zero or more named, typed scalar output parameters
zero or more "rowsets", each of which is an ordered list of zero or more rows.
Within a rowset, all rows have the same number (one or more) of named, typed columns. The column names do not have to be distinct within a rowset.
SQL Server does not recognize any special cases, like a single rowset with a single row or a single column; or a single output parameter.
Other database systems are slightly different.
I have a query that has
... WHERE PRT_STATUS='ONT' ...
The prt_status field is defined as CHAR(5) though. So it's always padded with spaces. The query matches nothing as the result. To make this query work I have to do
... WHERE rtrim(PRT_STATUS)='ONT'
which does work.
That's annoying.
At the same time, a couple of pure-java DBMS clients (Oracle SQLDeveloper and AquaStudio) I have do NOT have a problem with the first query, they return the correct result. TOAD has no problem either.
I presume they simply put the connection into some compatibility mode (e.g. ANSI), so the Oracle knows that CHAR(5) expected to be compared with no respect to trailing characters.
How can I do it with Connection objects I get in my application?
UPDATE I cannot change the database schema.
SOLUTION It was indeed the way Oracle compares fields with passed in parameters.
When bind is done, the string is passed via PreparedStatement.setString(), which sets type to VARCHAR, and thus Oracle uses unpadded comparision -- and fails.
I tried to use setObject(n,str,Types.CHAR). Fails. Decompilation shows that Oracle ignores CHAR and passes it in as a VARCHAR again.
The variant that finally works is
setObject(n,str,OracleTypes.FIXED_CHAR);
It makes the code not portable though.
The UI clients succeed for a different reason -- they use character literals, not binding. When I type PRT_STATUS='ONT', 'ONT' is a literal, and as such compared using padded way.
Note that Oracle compares CHAR values using blank-padded comparison semantics.
From Datatype Comparison Rules,
Oracle uses blank-padded comparison
semantics only when both values in the
comparison are either expressions of
datatype CHAR, NCHAR, text literals,
or values returned by the USER
function.
In your example, is 'ONT' passed as a bind parameter, or is it built into the query textually, as you illustrated? If a bind parameter, then make sure that it is bound as type CHAR. Otherwise, verify the client library version used, as really old versions of Oracle (e.g. v6) will have different comparison semantics for CHAR.
If you cannot change your database table, you can modify your query.
Some alternatives for RTRIM:
.. WHERE PRT_STATUS like 'ONT%' ...
.. WHERE PRT_STATUS = 'ONT ' ... -- 2 white spaces behind T
.. WHERE PRT_STATUS = rpad('ONT',5,' ') ...
I would change CHAR(5) column into varchar2(5) in db.
You can use cast to char operation in your query:
... WHERE PRT_STATUS=cast('ONT' as char(5))
Or in more generic JDBC way:
... WHERE PRT_STATUS=cast(? as char(5))
And then in your JDBC code do use statement.setString(1, "ONT");