A very quick question
I have a read-only access to Oracle database. However, I would like to check the variable type list e.g.
Var1 Varchar(30)
Var2 Numeric
etc...
What is the best code to do this?
Thanks
I'm guessing you want to view the data types for the columns of a table. If so:
select
column_id,
table_name,
column_name,
decode(data_type,
'NUMBER', 'NUMBER('||data_precision||decode(data_scale,0,null,','||data_scale)||')',
'VARCHAR2', 'VARCHAR2('||data_length||')',
'DATE', 'DATE',
data_type||'('||data_length||')'
) type,
decode(nullable,'N','NOT NULL') n
from user_tab_columns
where table_name = 'MY_TABLE_NAME'
order by 1
If the table resides in another schema, use instead:
...
from all_tab_columns
where table_name = 'MY_TABLE_NAME' and owner='CORRECT_USERNAME'
Related
in oracle database on linux server;
desc table_x; => getting data
select * from table_x; => getting data
SELECT table_name from all_tables; => it is not in the list
How can I get this table to appear in the list?
Thanks.
Looks like it isn't a table that is contained in all_tables. What is it, then?
Might be a synonym, so try
select * from all_synonyms where synonym_name = 'TABLE_X';
Or, a view:
select * From all_views where view_name = 'TABLE_X';
I have a PL/SQL procedure that currently gets data from an XML service and only does inserts.
xml_data := xmltype(GET_XML_F('http://test.example.com/mywebservice');
--GET_XML_F gets the XML text from the site
INSERT INTO TEST_READINGS (TEST, READING_DATE, CREATE_DATE, LOCATION_ID)
SELECT round(avg(readings.reading_val), 2),
to_date(substr(readings.reading_dt, 1, 10),'YYYY-MM-DD'), SYSDATE,
p_location_id)
FROM XMLTable(
XMLNamespaces('http://www.example.com' as "ns1"),
'/ns1:test1/ns1:series1/ns1:values1/ns1:value'
PASSING xml_data
COLUMNS reading_val VARCHAR2(50) PATH '.',
reading_dt VARCHAR2(50) PATH '#dateTime') readings
GROUP BY substr(readings.reading_dt,1,10), p_location_id;
I would like to be able to insert or update the data using a merge statement in the event that it needs to be re-run on the same day to find added records. I'm doing this in other procedures using the code below.
MERGE INTO TEST_READINGS USING DUAL
ON (LOCATION_ID = p_location_id AND READING_DATE = p_date)
WHEN NOT MATCHED THEN INSERT
(TEST_reading_id, site_id, test, reading_date, create_date)
VALUES (TEST_readings_seq.nextval, p_location_id,
p_value, p_date, SYSDATE)
WHEN MATCHED THEN UPDATE
SET TEST = p_value;
The fact that I'm pulling it from an XMLTable is throwing me off. Is there way to get the data from the XMLTable while still using the (much cleaner) merge syntax? I would just delete the data beforehand and re-import or use lots of conditional statements, but I would like to avoid doing so if possible.
Can't you simply put your SELECT into MERGE statement?
I believe, this should look more less like this:
MERGE INTO TEST_READINGS USING (
SELECT
ROUND(AVG(readings.reading_val), 2) AS test
,TO_DATE(SUBSTR(readings.reading_dt, 1, 10),'YYYY-MM-DD') AS reading_date
,SYSDATE AS create_date
,p_location_id AS location_id
FROM
XMLTable(
XMLNamespaces('http://www.example.com' as "ns1")
,'/ns1:test1/ns1:series1/ns1:values1/ns1:value'
PASSING xml_data
COLUMNS
reading_val VARCHAR2(50) PATH '.',
reading_dt VARCHAR2(50) PATH '#dateTime'
) readings
GROUP BY
SUBSTR(readings.reading_dt,1,10)
,p_location_id
) readings ON (
LOCATION_ID = readings.location_id
AND READING_DATE = readings.reading_date
)
WHEN NOT MATCHED THEN
...
WHEN MATCHED THEN
...
;
What is the data type of ORA_ROWSCN? It seems to be NUMBER but I cannot find it specified in the documentation.
declare
myscn ???;
begin
select ora_rowscn into myscn from t where ...;
end;
It is a NUMBER. You can see yourself by creating a simple view and describing it (or selecting from *_tab_columns). Here's a simple sqlfiddle demonstration
create table foo (
col1 number
);
create view vw_foo
as
select col1, ora_rowscn scn
from foo;
select *
from user_tab_cols
where table_name = 'VW_FOO';
If you want more detail than you'd probably ever care about on the format of the SCN (system change number), here is one decent article
I created the following table:
Create table temp.test(c1 VARCHAR2(10 BYTE));
I was trying to use CHAR_USED to determine whether the column size is in BYTES or CHARS but all I am getting back is '0 rows fetched from 1 column'. The database version i am using is Oracle 11g. Does anyone have a clue as to why it is not return the semantic length information for this table?
The query used are as follows:
select CHAR_USED from all_tab_columns where table_name='temp.test'
select CHAR_USED from all_tab_columns where table_name='test' and owner = 'temp'
Assuming that you are not using case-sensitive identifiers (which you are not and should not), object names are stored in the data dictionary in upper case. So when you query a table like all_tab_columns, you'd need to use upper-case
SELECT column_name, char_used
FROM all_tab_columns
WHERE table_name = 'TEST'
AND owner = 'TEMP'
For a table in oracle, I can query "all_tab_columns" and get table column information, like the data type, precision, whether or not the column is nullable.
In SQL Developer or TOAD, you can click on a view in the GUI and it will spit out a list of the columns that the view returns and the same set of data (data type, precision, nullable, etc).
So my question is, is there a way to query this column definition for a view, the way you can for a table? How do the GUI tools do it?
You can use user_tab_columns (or all_tab_columns and dba_tab_columns respectively) regardless if table_name refers to a view or a table.
View columns appear in all_tab_columns, so you can query them just as you can tables.
Just simply write this query:
SQL> desc TABLE/VIEW NAME;
For example if the table/view name is "department" Then just write:
SQL> desc department;
This will give the list of all fields, it's type and default Null info of the table or view.
you can use the ANSI catalog views, should work for most RDBMs
select *
from information_schema.columns c
join information_schema.tables t on c.table_name = t.table_name
where table_type = 'view'