what is the format of schema when we create a new table using Voltdb?
I'm a newbie. I have researched for a while and read the explanation in this https://docs.voltdb.com/UsingVoltDB/ChapDesignSchema.php
Please give me more detal about the schema format when I create a new table.
Another quesiton is What is the call flow of the system, since a request comes to the system until a response is create.
Which class/function does it go through in the system.
Since VoltDB is a SQL compliant database, you would create a new table in VoltDB just as you would create a new table in any other traditional relational database. For e.g.,
CREATE TABLE MY_TABLE (id INTEGER NOT NULL, name VARCHAR(10));
You can find all the SQL DDL statements that you can run on VoltDB here
1.Make file yourSchemaName.sql anywhere in the system. Suppose yourSchemaName.sql looks like this
CREATE TABLE Customer (
CustomerID INTEGER UNIQUE NOT NULL,
FirstName VARCHAR(15),
LastName VARCHAR (15),
PRIMARY KEY(CustomerID)
);
2.fire sqlcmd in CLI inside folder where you have installed the voltdB.
if you haven't set the path then you have to type /bin/sqlcmd.
After firing the command, a simple way to load schema in your voltdB database is by typing /path/to/yourSchemaName.sql; command inside the sqlcmd utility and the schema named yourSchemaName.sql will be imported inside the database.
VoltdB is relational database,so Now you can use all of sql database queries inside this database.
Related
I created database using SQL in hive.
And I looked for the database using HDFS.
But I couldn't find database in HDFS.
In hive:
CREATE DATABASE practice
LOCATION '/user/hive/warehouse'/
Checking:
hdfs dfs -ls /user/hive/warehouse
There is nothing in warehouse.
In addition, I created a table in a specific database in hive.
But, using Hue, I could see the table in the default location.
I wanna insert the table into a specific database location.
CREATE TABLE prac (
id INT,
title STRING,
salary INT,
posted TIMESTAMP
)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY ','
LOCATION '/user/hive/warehouse/practice.db/prac';
I couldn't find the table prac in the database practice in Hue and HDFS.
How can I see the database in HDFS?
And I also wanna know how to see the table in the specific database location.
Try by specifying db name while creating hive table prac by default hive creates tables in default database.
Example:
hive> CREATE DATABASE practice LOCATION '/user/hive/warehouse/practice.db';
hive> CREATE TABLE `practice.prac` ( id INT, title STRING, salary INT, posted TIMESTAMP ) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' LOCATION '/user/hive/warehouse/practice.db/prac';
Try using below command:
CREATE DATABASE practice
LOCATION '/user/hive/warehouse/practice.db';
hive by default uses '/user/hive/warehouse/' directory to create databases under this location. So while creating database, If you don't provide the location it will pick the database location like this '/user/hive/warehouse/practice.db'.
You can choose any location over hdfs until you have read and write permission over that location.
Here is the scenario for which Iam trying to create a SSIS package using VS2013. We have SQLServer2014 servers - A & B.
From ServerA.Database1, need to copy data for few specific tables to ServerB.Database2.
But before copy, have to drop the table and recreate the table at destination (ServerB.Database2) using the table schema from source (ServerA.Database1) because of schema changes happening frequently. Need to schedule this weekly.
How to accomplish using SSIS (how to retrieve source table schema information in the ssis package so that it will be used to create a table at the destination) ? or any other way ?
Thanks
Bhanu.
Add an execute sql task and provide sql text 'Drop table tablename' and then create table tablename (variables and datatypes)
Below approach will require a Linked Server. No need to worry about table schema.
Drop table TargetServer.database.dbo.tablename
Insert * into TargetServer.database.dbo.tablename from SourceServer.database.dbo.tablename
I have a table. For example:
CREATE TABLE temp AS SELECT * FROM range(20)
How i can create in sqlite a new database with one command with the table temp?
Since your in sqlite, in the command line just type:
sqlite3 datbase_name.db
This will create a new database called database_name.db, now to create your table to this database just type:
sqlite3 database_name.db "CREATE TABLE .......;"
Type your create table statement inside the quotes.
For more info, please take a look at their documentation.
I think that would depend on the DBMS but this may be what you're looking for.
COPY Command Syntax
"COPY {FROM database | TO database | FROM database TO database} {APPEND|CREATE|INSERT|REPLACE} destination_table [(column, column, column, ...)] USING query"
http://docs.oracle.com/cd/B19306_01/server.102/b14357/apb.htm
I want to create a copy of a table, say TestTable, with a new name, say TestTableNew, in the same database with the use of an SSIS package. I've created a "Transfer SQL Server Objects Task" for this with the source database specified as both the SourceDatabase and the DestinationDatabase. When I run this task, the original table TestTable is overwritten with a new -empty- TestTable.
This might well be something really obvious that I've overlooked, but can I somehow specify another name for the destination table somewhere in this transfer task? Or should I solve this in another way?
You can't use the "Transfer SQL Server Objects Task" to copy a table to the same database because there isn't an option to specify the new table name. You would be copying table "TestTable" to table "TestTable", which will fail because they both have the same name.
You can set the "DropObjectsFirst" property to true, but that will make you lose your original table and its data, which I think you did on your test, otherwise you would have received a failure message.
The best option here is to use an "Execute SQL Task" to create the structure of your TestTableNew based on your TestTable and then do a simple OleDBSource -> OleDBDestination transformation to load all the data from one table to another.
My knowledge of SSIS is very limited but I assume you can run sql commands passing in
parameters and therefore generating something like the following dynamically
select *
insert into TestTableNew
from TestTable
I have 2 Oracle questions
How do I translate this SQL Server statement to work on Oracle?
Create table MyCount(Line int identity(1,1))
What is the equivalent of SQL Servers Image type for storing pictures in an Orace database?
You don't need to use triggers for this if you manage the inserts:
CREATE SEQUENCE seq;
CREATE TABLE mycount
(
line NUMBER(10,0)
);
Then, to insert a value:
INSERT INTO mycount(line) VALUES (seq.nextval);
For images, you can use BLOBs to store any binary data or BFILE to manage more or less as a BLOB but the data is stored on file system, for instance a jpg file.
References:
Create Sequence reference.
Create table reference.
Oracle® Database Application Developer's Guide - Large Objects.
1: You'll have to create a sequence and a trigger
CREATE SEQUENCE MyCountIdSeq;
CREATE TABLE MyCount (
Line INTEGER NOT NULL,
...
);
CREATE TRIGGER MyCountInsTrg BEFORE INSERT ON MyCount FOR EACH ROW AS
BEGIN
SELECT MyCountIdSeq.NEXTVAL INTO :new.Line
END;
/
2: BLOB.
Our tools can answer these questions for you. I'm talking about Oracle SQL Developer.
First - it has a Create Table wizard - and 12/18c Database supports native implementation of Identity columns.
And your new table DDL
CREATE TABLE MYCOUNT
(
LINE INT GENERATED ALWAYS AS IDENTITY NOT NULL
);
Also, we have a Translator - it can take SQL Server bits and turn them into equivalent Oracle bits. There's a full-blown migration wizard which will capture and convert your entire data model.
But for one-offs, you can use your Scratchpad. It's available under the Tools, Migrations menu.
Here it is taking your code and giving you something that would work in any Oracle Database.
Definitely use the identity feature in 12/18c if you're on that version of Oracle. Fewer db objects to maintain.