Please tell me how can I move dependencies (such as PK, FK and indexes) from one table to another within the same database in Oracle? The second table is a copy of the first, only created later for partition reasons. Thank you in advance! :)
You could look at using the dictionary views in oracle, specifically the USER_CONSTRAINTS view. Then either construct a SQL statement dynamically or use DBMS_METADATA.get_ddl procedure to get the ddl for the constraint. You could do a REPLACE on the SQL to replace the original table name and constraint name with a new constraint name and the name of the new table.
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I am new to Hive and have some problems. I try to find a answer here and other sites but with no luck... I also tried many different querys that come to my mind, also without success.
I have my source table and i want to create new table like this.
Were:
id would be number of distinct counties as auto increment numbers and primary key
counties as distinct names of counties (from source table)
You could follow this approach.
A CTAS(Create Table As Select)
with your example this CTAS could work
CREATE TABLE t_county
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
STORED AS TEXTFILE AS
WITH t AS(
SELECT DISTINCT county, ROW_NUMBER() OVER() AS id
FROM counties)
SELECT id, county
FROM t;
You cannot have primary key or foreign keys on Hive as you have primary key on RBDMSs like Oracle or MySql because Hive is schema on read instead of schema on write like Oracle so you cannot implement constraints of any kind on Hive.
I can not give you the exact answer because of it suppose to you must try to do it by yourself and then if you have a problem or a doubt come here and tell us. But, what i can tell you is that you can use the insertstatement to create a new table using data from another table, I.E:
create table CARS (name string);
insert table CARS select x, y from TABLE_2;
You can also use the overwrite statement if you desire to delete all the existing data that you have inside that table (CARS).
So, the operation will be
CREATE TABLE ==> INSERT OPERATION (OVERWRITE?) + QUERY OPERATION
Hive is not an RDBMS database, so there is no concept of primary key or foreign key.
But you can add auto increment column in Hive. Please try as:
Create table new_table as
select reflect("java.util.UUID", "randomUUID") id, countries from my_source_table;
I have two instances of the same database, but data is only committed to the "original" one. I need to copy inserted data from certain tables and commit them to the same tables in the second DB automatically. How can I do it?
I've already created synonyms for the tables in the second DB on original and within a specially prepared trigger I tried to use INSERT INTO ... statement with :new. but it is causing the data to not be committed anywhere and I receive Oracle Errors like:
ORA-02291: integrity constraint (PRDBSHADOW.FK_ED_PHY_ENT) violated.
Here is my trigger code
create or replace TRIGGER INS_COPY_DATA
AFTER INSERT ON ORIGDB.TABLE_A
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
BEGIN
insert into COPY_TABLE_A(val1,val2,val3,val4) values (:new.val1, :new.val2, :new.val3, :new.val4);
END;
I think the entry in parent table is missing here. At least the FK ending of constraint is telling me so.
It means you need to insert first all the data into a "parent" table in order to be able to insert records in a "child".
For example the table auto_maker is having 3 rows only: Audi, Peugeot, and Honda.
Another table named "model" has 2 columns "maker" and "model". "maker" is a foreign key referencing to the "auto_maker" table.
It means in the models table are only the records allowed whose "maker" column value exists in "auto_maker" table.
In other words only these are available:
maker model
Audi A4
Peugeot 308
Honda Accord
Of course you can enter every model you wish, but "maker" value has to exist in the auto_maker table.
This is what probably happen - the trigger tries to insert a data in a column which is referencing to a "parent" table and the :new value just doesn't exist.
The following script will let you know what table you need to fill first.
select aic.index_owner, aic.table_name, aic.column_name
from all_constraints uc,
all_ind_columns aic
where aic.INDEX_NAME = uc.r_constraint_name
and uc.table_name = 'TABLE_A'
and uc.constraint_type = 'R';
If the query returns something just create similar triggers on those tables with similar logic you already have
When I need to change a column into a partition (convert normal column as partition column in hive), I want to create a new table to copy all columns except one. I currently have >50 columns in the original table. Is there any clean way of doing that?
Something like:
CREATE student_copy LIKE student EXCEPT age and hair_color;
Thanks!
You can use a regex:
CTAS using REGEX column spec. :
set hive.support.quoted.identifiers=none;
CREATE TABLE student_copy AS SELECT `(age|hair_color)?+.+` FROM student;
set hive.support.quoted.identifiers=column;
BUT (as mentioned by Kishore Kumar Suthar :
this will not create a partitioned table, as that is not supported with CTAS (Create Table As Select).
Only way I see for you to get your partitioned table is by getting the complete create statement of the table (as mentioned by Abraham):
SHOW CREATE TABLE student;
Altering it to create a partition on the column you want. And after that you can use the select with regex when inserting into the new table.
If your partition column is already part of this select, then you need to make sure it is the last column you insert. If it is not you can exclude that column in the regex and including it as last. Also if you expect several partitions to be created based on your insert statement you need to enable 'dynamic partitioning':
set hive.support.quoted.identifiers=none;
set hive.exec.dynamic.partition=true;
set hive.exec.dynamic.partition.mode=nonstrict;
INSERT INTO TABLE student_copy PARTITION(partcol1) SELECT `(age|hair_color|partcol1)?+.+`, partcol1 FROM student;
set hive.support.quoted.identifiers=column;
the 'hive.support.quoted.identifiers=none' is required to use the backticks '`' in the regex part of the query. I set this parameter to it's original value after my statement: 'hive.support.quoted.identifiers=column'
CREATE TABLE student_copy LIKE student;
It just copies the source table definition.
CREATE TABLE student_copy AS select name, age, class from student;
Target cannot be partitioned table.
Target cannot be external table.
It copies the structure as well as the data
I use below command to get the create statement of existing table.
SHOW CREATE TABLE student;
Copy the result and modify that based on your requirement for new table and run the modified command to get the new table.
I'm trying to move the data from one table TABLE5 another one TABLE5_BKP.
CREATE TABLE TABLE5_BKP AS SELECT * FROM TABLE5;
The table created and the data moved. when I checked the constraints,
The primary key,foreign key etc are not generated but all other constraints like,
SYS_C2211111 Check "COLUMN1" IS NOT NULL
etc are created. What to do in this case? Need to create the primary key,foreign key etc separately? What about indexes and other parameters, which I was not able to check.
You can't implicitly create PK, FK, Indexes, etc. just using
CREATE TABLE tablename AS SELECT *...
You have to specify them after creating. Also I suggest you to use oracle tools, like exp/imp, data pump, etc. if you want to move the database structure from one database to another.
I want to create a table (lets say table_copy) which has same columns as other table (lets call it table_original) in Oracle database, so the query will be like this :
create table table_copy as (select * from table_original where 1=0);
This will create a table, but the constraints of table_original are not copied to table_copy, so what should be done in this case?
Only NOT NULL constraints are copied using Create Table As Syntax (CTAS). Others should be created manually.
You might however query data dictionary view to see the definitions of constraints and implement them on your new table using PL/SQL.
The other tool that might be helpful is Oracle Data Pump. You could import the table using REMAP_TABLE option specifying the name for the new table.
Use a database tool to extract the DDL needed for the constraints (SQL Developer does the job). Edit the resulting script to match the name of the new class.
Execute the script.
If you need to do this programmatically you can use a statement like this:
DBMS_METADATA.GET_DDL('TABLE','PERSON') from DUAL;