PL/SQL :: How To Retrieve Information About Columns Of Tables
Nov 16, 2012
I am trying to get information about the columns of tables in Oracle databases. In MySQL, show columns provides good deal of information.But in Oracle, we do not have such equivalent call."describe" shows only the primary key.
But it does not show whether any column has unique constraint or an index.
I created a column in a table with unique constraint (but not a primary key), but it was not listed with CONSTRAINT_TYPE = 'U' in dba_constraints view, but was listed with CONSTRAINT_TYPE = 'C' - Check constraint.
How can i retrieve which tables have composite primary keys, and only one of the primary key columns is a foreign key to another table?
Like: CREATE TABLE club ( clubId NUMBER, name VARCHAR(20) NOT NULL, PRIMARY KEY (ClubId) );
CREATE TABLE team ( teamid NUMBER(10), clubid NUMBER(10), teamname VARCHAR(10) NOT NULL, PRIMARY KEY (teamid, clubid), FOREIGN KEY (clubid) REFERENCES club (clubid));So in this case, the team table
I WANT to RETRIEVE all the INFORMATION of DEPT ALONG with TWO EMPLOYEES of each DEPARTMENT.is any OTHER WAY to DO THIS due to performance in Oracle 10g
UDI-31626: operation generated ORACLE error 31626 ORA-31626: job does not exist ORA-39086: cannot retrieve job information ORA-06512: at "SYS.DBMS_DATAPUMP", line 3326 ORA-06512: at "SYS.DBMS_DATAPUMP", line 4551 ORA-06512: at line 1
I would like to retrieve only the latest repair information based on the latest date regardless of the other information, so I would like to query only items 3 and 5 in the following example.
I renamed 100 tables and recreated them, now I need to copy supplemental login information from renamed table to new tables. Environment is oracle 10G.
I have one query regarding how to retrieve the CLOB data.
The requirement is something that in the select statement there are around 20+ columns which i need to retrieve from around 5 tables after joining.
Since the result set after joining also will get duplicate values i need to use distinct keyword to filter the resultset. But in the 20+ columns there are 2 CLOB data columns which i need to retrieve.
Whenever i use DISTINCT i'm getting ORA-00932: inconsistent datatypes: expected - got CLOB error. I know that DISTINCT keyword cannot be used for CLOB datatypes.
One of the developer dropped 18 tables by mistake on USER@db schema. Developer asked whether I can restore those tables, but unfortunately they are not in the recycle bin. Developer is re-creating the table now though. But I am just curious whether we need to change these parameters (db_recycle_cache_size) in order support any similar requests in the future.
NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ db_recycle_cache_size big integer 0 recyclebin string on
I have to compare 2 tables on a columns's value.The 2 tables have same column as Regn_no.I just need to have the result in True Or False from a Query if the particular value of Regn_no is found in both the tables.
Temporarily I using a bit different and not good query which is as follows:
select count(*) from tab1 where regn_no in (select regn_no from tab2) and regn_no = 'UP78AN7890';
sample1 A B C D E F -------------------------- 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5
sample2 G H I J ---------------- 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5
consider the above tables what i want is some thing like this
output G H I J A -----------------
this can also be done through a select statement through choosing the columns which you want i don want thatbut what i want is columns of entire table sample2 and only one column in sample1
Desc Table A (account) Account1_id Account2_id name, empid
Table B (Bill ) BillNo Advertiserid agencyid total vvalue
I need to pick up total value from table B where the unique combination of advertiser-Agency id is the same as the given account1_id -Account2_id combination in table A for each employee id.
In other words my output should be like
Empid | Account_id (should be same as advertiserid)| Account2_id (same as agencyid) | sum(total_value) for this adv-agency combination.....
objective: Get the total value from table B for each unique account1-account2 combination (advertiser-agency in other words) .
I am not sure if I should use a correlated subquery or how to handle the situation....Right now I am just checking the two columns separately like this:
select.......from a,b where b.advertiser_id = a.account1_id and b.agencyid = b.account2id
Is it correct to do so? I have a feeling that I am missing something if I join them separately like this.
I've recieved a recent request wherein the requirement is to swap values between columns across multiple tables in a database.Following is a visual sample of what needs to be done.
I have a large table with 450 column and we are only using nearly 170 columns and our BD block size is 8k.The DBA informed that there is an row chaining happening in the Database.My question is if we have data available in 170 column .why row chaining is happening.
The DBA informed us to remove the unnecessary columns .. Does those empty columns have any impact on the chaining.If we increase the size of DB block to 32k . does it will resolve the issue.
im trying to select columns from different tables dynamically in a function . The parameter for the function will be table name and column id's, In this number of columns may vary . Is it possible to have dynamic %rowtype to store the cursor value in it.
I am trying to update multiple columns from one table based on the results of another table So I have 3 tables as follows
HISTORYSUMM_SNAPADM_CHOICE My SQL code is loosely SELECT SUM(H.HIS1), SS.SNAP1, AC.ADM1FROMHISTORY H, SUMM_SNAP SS,ADM_CHOICE ACWHERE H.HIS2=SS.SNAP2AND SS.SNAP3=AC.ADM2GROUP BY SS.SNAP1, AC.ADM1
This works, and I am able to SUM the column as I need with the right numbers. I altered the SUMM_SNAP table and now I want this summarized column to be in the table I tried using UPDATE, but there is no FROM clause to let me do the table join/group by
UPDATE SUMM_SNAPSET SUMM_SNAP.SNAP3=SUM(H.HIS1)FROMHISTORY H, SUMM_SNAP SS,ADM_CHOICE AC WHERE H.HIS2=SS.SNAP2AND SS.SNAP3=AC.ADM2 GROUP BY SS.SNAP1, AC.ADM1
The above is obviously wrong - but just trying to show whatI was thinking What would be the best method to get the numbers from the SUM into a table?
i have two tables test1 and test2. i want to update the column(DEPT_DSCR) of both the tables TEST1 and TEST2 using select for update and current of...using cursor.
I have a code written as follows :
DECLARE v_mydept1 TEST1.DEPT_CD%TYPE; v_mydept2 TEST2.DEPT_CD%TYPE; CURSOR C1 IS SELECT TEST1.DEPT_CD,TEST2.DEPT_CD FROM TEST1,TEST2 WHERE TEST1.DEPT_CD = TEST2.DEPT_CD AND TEST1.DEPT_CD = 'AA' FOR UPDATE OF TEST1.DEPT_DSCR,TEST2.DEPT_DSCR; [code].......
The above code when run says that it runs successfully. But it does not updates the desired columns[DEPT_DSCR].
It only works when we want to update single or multiple columns of same table...i.e. by providing these columns after "FOR UPDATE OF" I am not sure what is the exact problem when we want to update multiple columns of different tables.
As the title of this topic illustrates, i'm having trouble dumping relevant data from columns of different tables. I am using isql*plus. I have three tables appropriatly related. A 'course' table, 'student' and 'next_of_kin' tables. I have many students enrolled on various courses but only a hanfull of courses offer the module option 'Database Systems'. I have no 'module' table but i know the three course names which provide the module option. I intend on producing a report hich lists all students enrolled on the courses which provid the module option 'Database Systems'.
I have attempted the report but i keep getting a 'cartesian product' displaying all next_of_kin names instead of the appropriate. Also i am struggling to come up with the right WHERE statement to depict only the three courses which provide the module option 'Database Systems' as defined by 'courseNo' in both 'course' and 'student' tables.
Here is the most recent attempt:
--set echo off --set pagesize 24 --set feedback off --set linesize 78 col A format 99999999 heading 'Student No'
I have a two different Databases. I created a db link in DB 1 to connect to DB 2 and it is working fine when I select data from any table. but I have one table in the DB2 which has a column with user defined data type . so when I try to select this column from DB 2 by using the DB link it gives me this error :ORA-22804 remote operations not permitted on object tables or user-defined type columns.
I want to create a report by using one field and one text as columns name in layout but display the all the columns. I mention the 5 column names in query.how can I write function in summary column.
I am running a fairly busy Oracle 10gR2 DB, one of the tables has about 120 columns and this table receives on average 1500 insertions per second. The table is partitioned and the partitioning is based on the most important of the two timestamp columns. There are two timestamps, they hold different times.
Out of these 120 columns, about 15 need to be indexed. Out of the 15 two of them are timestamp, at least one of these two timestamp columns is always in the where clause the queries.
Now the challenge is, the queries we run can have any combination of the 13 other columns + one timestamp. In reality the queries never have more than 7 or 8 columns in the where clause but even if we had only 4 columns in the where clause we would still have the same problem.
So if I create one concatenated index for all these columns it will not be very efficient because after the 4th or 5th column the sorting would no longer be very useful and I believe the optimiser would simply not use the rest of the index. So queries that use the leading columns of the index in sequence work well, but if I need to query the 10th column the I have performance issues.
Now, if I create multiple single column indexes oracle will have to work a lot harder to maintain all these indexes and it will create performance issues (I have tried that). Besides, if I have multiple single column indexes the optimiser will do nested loops twice or three times and will hit only the first few columns of the where clause so I think it will kind of be the same as the long concatenated index.
What I am trying to do is exactly what the Bitmap index would do, it would be very good if I could use the AND condition that a Bitmap index uses. This way I could have N number of single column indexes which the optimiser could pick from and serve the query with exactly the ones it needs. But unfortunately using the Bitmap index here is not an option given the large amount of inserts that I get on this table.
I have been looking for alternatives, I have considered creating multiple shorter concatenated indexes but this still would not address the issue since many queries would still not be served properly and therefore would take a very long time to complete.
What I had in mind would be some sort of multidimensional index, I am not even sure if such thing exists. But essentially it would be some sort of index that could serve a query efficiently regardless of the fact that the where clause has the 1st, 3rd and last columns of the index.
So considering how widely used Oracle is and how many super large databases there are out there, this problem must be common.
