I have connected to my new DB2 database via JDBC and am trying to create and insert a temporary table:
String createTemporaryTable = "declare global temporary table temporary_table (RECORD smallint) ON COMMIT PRESERVE ROWS in TEMPTABLESPACE";
statement.execute(createTemporaryTable);
String insert = "INSERT INTO temporary_table (RECORD) VALUES (1)";
statement.execute(insert);
connection.commit();
This results in
"DB2 SQL Error: SQLCODE=-204, SQLSTATE=42704"
Creating a normal table and inserting this way results in no errors. Is there something I need to configure?
You must refer to the temporary table as being in the schema session. Try the insert like:
String insert = "INSERT INTO session.temporary_table (RECORD) VALUES (1)";
session is implicit when declaring the table, but for clarity I usually declare it as:
declare global temporary table session.temporary_table (...
Related
How to create a global temporary table with same table structure to that of a existing table?
I know this concept is available in SQL server like "select * into #temp123 from abc". But I want to perform the same in Oracle.
Create global temporary table mytemp
as
select * from myTable
where 1=2
Global temporary tables in Oracle are very different from temporary tables in SQL Server. They are permanent data structures, it is merely the data in them which is temporary (limited to the session or transaction, depending on how a table is defined).
Therefore, the correct way to use global temporary tables is very different to how we use temporary tables in SQL Server. The CREATE GLOBAL TEMPORARY TABLE statement is a one-off exercise (like any other table). Dropping and recreating tables on the fly is bad practice in Oracle, which doesn't stop people wanting to do it.
Given the creation of a global temporary table should a one-off exercise, there is no real benefit to using the CREATE TABLE ... AS SELECT syntax. The statement should be explicitly defined and the script stored in source control like any other DDL.
You have tagged your question [oracle18c]. If you are really using Oracle 18c you have a new feature open to you, private temporary tables, which are closer to SQL Server temporary tables. These are tables which are genuinely in-memory and are dropped automatically at the end of the transaction or session (again according to definition). These are covered in the Oracle documentation but here are the headlines.
Creating a private temporary table data with a subset of data from permanent table T23:
create table t23 (
id number primary key
, txt varchar2(24)
);
insert into t23
select 10, 'BLAH' from dual union all
select 20, 'MEH' from dual union all
select 140, 'HO HUM' from dual
/
create private temporary table ORA$PTT_t23
on commit preserve definition
as
select * from t23
where id > 100;
The ORA$PTT prefix is mandatory (although it can be changed by setting the init.ora parameter PRIVATE_TEMP_TABLE_PREFIX, but why bother?
There after we can execute any regular DML on the table:
select * from ORA$PTT_t23;
The big limitation is that we cannot use the table in static PL/SQL. The table doesn't exist in the data dictionary as such, and so the PL/SQL compiler hurls - even for anonymous blocks:
declare
rec t23%rowtype;
begin
select *
into rec
from ORA$PTT_t23';
dbms_output.put_line('id = ' || rec.id);
end;
/
ORA-06550: line 6, column 10: PL/SQL: ORA-00942: table or view does not exist
Any reference to a private temporary table in PL/SQL must be done with dynamic SQL:
declare
n pls_integer;
begin
execute immediate 'select id from ORA$PTT_t23' into n;
dbms_output.put_line('id = ' || n);
end;
/
Basically this restricts their usage to SQL*Plus (or sqlcl scripts which run a series of pure SQL statements. So, if you have a use case which fits that, then you should check out private temporary tables. However, please consider that Oracle is different from SQL Server in many aspects, not least its multi-version consistency model: readers do not block writers. Consequently, there is much less need for temporary tables in Oracle.
In the SQL Server's syntax the prefix "#" (hash) in the table name #temp123 means - create temporary table that is only accessible via the current session ("##" means "Global").
To achive exactly the same thing in Oracle you can use private temporary tables:
SQL> show parameter private_temp_table
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
private_temp_table_prefix string ORA$PTT_
create table mytab as
select 1 id, cast ('aaa' as varchar2 (32)) name from dual
;
create private temporary table ora$ptt_mytab on commit preserve definition as
select * from mytab where 1=0
;
Private TEMPORARY created.
Afterwards you can use these tables in SQL and PL/SQL blocks:
declare
r mytab%rowtype;
begin
insert into ora$ptt_mytab values (2, 'bbb');
select id + 1, name||'x' into r from ora$ptt_mytab where rownum = 1;
insert into ora$ptt_mytab values r;
end;
/
select * from mytab
union all
select * from ora$ptt_mytab;
ID NAME
---------- --------------------------------
1 aaa
2 bbb
3 bbbx
Some important restrictions on private temporary tables:
The name must always be prefixed with whatever is defined with the parameter PRIVATE_TEMP_TABLE_PREFIX. The default is ORA$PTT_.
You cannot reference PTT in the static statements of the named PL/SQL blocks, e.g. packages, functions, or triggers.
The %ROWTYPE attribute is not applicable to that table type.
You cannot define column with default values.
I'm completely new to Hive and Stack Overflow. I'm trying to create a table with complex data type "STRUCT" and then populate it using INSERT INTO TABLE in Hive.
I'm using the following code:
CREATE TABLE struct_test
(
address STRUCT<
houseno: STRING
,streetname: STRING
,town: STRING
,postcode: STRING
>
);
INSERT INTO TABLE struct_test
SELECT NAMED_STRUCT('123', 'GoldStreet', London', W1a9JF') AS address
FROM dummy_table
LIMIT 1;
I get the following error:
Error while compiling statement: FAILED: semanticException [Error
10044]: Cannot insert into target because column number type are
different 'struct_test': Cannot convert column 0 from struct to
array>.
I was able to use similar code with success to create and populate a data type Array but am having difficulty with Struct. I've tried lots of code examples I've found online but none of them seem to work for me... I would really appreciate some help on this as I've been stuck on it for quite a while now! Thanks.
your sql error. you should use sql:
INSERT INTO TABLE struct_test
SELECT NAMED_STRUCT('houseno','123','streetname','GoldStreet', 'town','London', 'postcode','W1a9JF') AS address
FROM dummy_table LIMIT 1;
You can not insert complex data type directly in Hive.For inserting structs you have function named_struct. You need to create a dummy table with data that you want to be inserted in Structs column of desired table.
Like in your case create a dummy table
CREATE TABLE DUMMY ( houseno: STRING
,streetname: STRING
,town: STRING
,postcode: STRING);
Then to insert in desired table do
INSERT INTO struct_test SELECT named_struct('houseno',houseno,'streetname'
,streetname,'town',town,'postcode',postcode) from dummy;
No need to create any dummy table : just use command :
insert into struct_test
select named_struct("houseno","house_number","streetname","xxxy","town","town_name","postcode","postcode_name");
is Possible:
you must give the columns names in sentence from dummy or other table.
INSERT INTO TABLE struct_test
SELECT NAMED_STRUCT('houseno','123','streetname','GoldStreet', 'town','London', 'postcode','W1a9JF') AS address
FROM dummy
Or
INSERT INTO TABLE struct_test
SELECT NAMED_STRUCT('houseno',tb.col1,'streetname',tb.col2, 'town',tb.col3, 'postcode',tb.col4) AS address
FROM table1 as tb
CREATE TABLE IF NOT EXISTS sunil_table(
id INT,
name STRING,
address STRUCT<state:STRING,city:STRING,pincode:INT>)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '.';
INSERT INTO sunil_table 1,"name" SELECT named_struct(
"state","haryana","city","fbd","pincode",4500);???
how to insert both (normal and complex)data into table
I wanted to insert some initial data into the table in hive, so I created below HQL,
INSERT OVERWRITE TABLE table PARTITION(dt='2014-06-26') SELECT 'key_sum' as key, '0' as value;
but it does not work.
There is another query like the above,
INSERT OVERWRITE TABLE table PARTITION(dt='2014-06-26') SELECT 'key_sum' as key, '0' as value FROM table limit 1;
But it also didn't work, as I see that the tables are empty.
How can I set the initial data into the table?
(There is the reason why I have to do self-join)
About first HQL it should have from clause, its missing so HQL failure,
INSERT OVERWRITE TABLE table PARTITION(dt='2014-06-26') SELECT 'key_sum' as key, '0' as value;
Regarding second HQL, from table should have atleast one row, so it can set the constant init values into your newly created table.
INSERT OVERWRITE TABLE table PARTITION(dt='2014-06-26') SELECT 'key_sum', '0' FROM table limit 1;
you can use any old hive table having data into it, and give a hit.
The following query works fine if we have already test table created in hive.
INSERT OVERWRITE TABLE test PARTITION(dt='2014-06-26') SELECT 'key_sum' as key, '0' as value FROM test;
I think the table which we perform insert should be created first.
I'm looking for the best way to change a data type of a column in a populated table. Oracle only allows changing of data type in colums with null values.
My solution, so far, is a PLSQL statement which stores the data of the column to be modified in a collection, alters the table and then iterates over the collection, restoring the original data with data type converted.
-- Before: my_table ( id NUMBER, my_value VARCHAR2(255))
-- After: my_table (id NUMBER, my_value NUMBER)
DECLARE
TYPE record_type IS RECORD ( id NUMBER, my_value VARCHAR2(255));
TYPE nested_type IS TABLE OF record_type;
foo nested_type;
BEGIN
SELECT id, my_value BULK COLLECT INTO foo FROM my_table;
UPDATE my_table SET my_value = NULL;
EXECUTE IMMEDIATE 'ALTER TABLE my_table MODIFY my_value NUMBER';
FOR i IN foo.FIRST .. foo.LAST
LOOP
UPDATE my_table
SET = TO_NUMBER(foo(i).my_value)
WHERE my_table.id = foo(i).id;
END LOOP;
END;
/
I'm looking for a more experienced way to do that.
The solution is wrong. The alter table statement does an implicit commit. So the solution has the following problems:
You cannot rollback after alter the alter table statement and if the database crashes after the alter table statement you will loose data
Between the select and the update users can make changes to the data
Instead you should have a look at oracle online redefinition.
Your solution looks a bit dangerous to me. Loading the values into a collection and subsequently deleting them fom the table means that these values are now only available in memory. If something goes wrong they are lost.
The proper procedure is:
Add a column of the correct type to the table.
Copy the values to the new column.
Drop the old column.
Rename the new column to the old columns name.
In Postgres, I can write
INSERT .. RETURNING *
To retrieve all values that had been generated during the insert. In Oracle, HSQLDB, I can use
String[] columnNames = ...
PreparedStatement stmt = connection.prepareStatement(sql, columnNames);
// ...
stmt.execute();
stmt.getGeneratedKeys();
To retrieve all values that had been generated. MySQL is a bit limited and only returns columns that are set to AUTO_INCREMENT. But how can this be done with Sybase SQL Anywhere? The JDBC driver does not implement these methods, and there is no INSERT .. RETURNING clause, as in Postgres. Is there way to do it, other than maybe running
SELECT ##identity
immediately after the insert?
My current implementation executes three consecutive SQL statements:
-- insert the data first
INSERT INTO .. VALUES (..)
-- get the generated identity value immediately afterwards
SELECT ##identity
-- get the remaining values from the record (possibly generated by a trigger)
SELECT * FROM .. WHERE ID = :previous_identity
The third statement can be omitted, if only the ID column is requested