Can I have multiple databases on oracle express edition? Please let me know what are steps to setup?
No. You can only have one XE database per server. You can have as many schemas in that database as you'd like. If you are coming from a background in other databases, what most databases refer to as a database is most equivalent to what Oracle refers to as a schema.
We were using separate virtual machine instances with Windows XP installed to create multiple oracle xe databases. However virtual machines consume too much memory for that simple task.
Now I'm using docker. Below you can find the docker image I'm currently using:
https://github.com/MaksymBilenko/docker-oracle-xe-11g
After you install docker to your computer, you can use the following commands to create the database:
# Create a folder for data in your home folder or somewhere else
mkdir /home/sedran/mydb1
# Download the docker image
docker pull sath89/oracle-xe-11g
# Create and start a new container with oracle-xe running on it
docker run --name oracle11g_mydb1 -d -p 1522:1521 -p 49163:8080 -v /home/sedran/mydb1:/u01/app/oracle sath89/oracle-xe-11g
Then you can connect to this DB from localhost:1522/XE
To create a second database, execute the following commands:
mkdir /home/sedran/mydb2
docker run --name oracle11g_mydb2 -d -p 1523:1521 -p 49164:8080 -v /home/sedran/mydb2:/u01/app/oracle sath89/oracle-xe-11g
The new DB will listen to port 1523 on localhost.
Do not forget to assign different ports, names and data folders (volumes) to every container.
Related
I have docker-compose.yml file and I start a container with DB via
docker-compose up -d db command.
I need to execute script by host machine that, briefly speaking, export dump to db in container.
So, now it looks like:
docker-compose up -d db
./script.sh
But I want to combine these two commands into one.
My question is "Is it possible?"
I found out that Docker Compose doesn't support this feature.
I know that I can create another script with these commands in it, but I want to leave only
docker-compose up -d db
UPD: I would like to mention that I am using mcr.microsoft.com/mssql/server:2017-latest image
Also, have to say one more time that I need to execute script exactly on host machine
You can't use the Docker tools to execute commands on the host system. A general design point around Docker is that containers shouldn't be able to affect the host.
Nothing stops you from writing your own shell script that runs on the host and does the steps you need:
#!/bin/sh
docker-compose -d up
./wait-for.sh localhost 1433
./script.sh
(The wait-for.sh script is the same as described in the answers to Docker Compose wait for container X before starting Y that don't depend on Docker health checks.)
For your use case it may be possible to run the data importer in a separate container. A typical setup could look like this; note that the importer will run every time you run docker-compose up. You may want to actually build this into a separate image.
version: '3.8'
services:
db: { same: as you have currently }
importer:
image: mcr.microsoft.com/mssql/server:2017-latest
entrypoint: ./wait-for.sh db 1433 -- ./script.sh
workdir: /import
volumes: [.:/import]
The open-source database containers also generally support putting scripts in /docker-entrypoint-initdb.d that get executed the first time the container is launched, but the SQL Server image doesn't seem to support this; questions like How can I restore an SQL Server database when starting the Docker container? have a complicated setup to replicate this behavior.
I installed oracle db version 19c in my docker environment with the following command:
docker run --name oracle19c --network host -p 1521:1521 -p 5500:5500
-v /opt/oracle:/u01/oracle oracle/database:19.3.0-ee
Then I connect to it with:
docker exec -ti oracle19c sqlplus system/oracle#orclpdb1
SQL>
Then I setup my database. Afterwards I want to import dummy data from a tbl file so I exit sqlplus and I use the command:
sqlldr userid=system control=/home/userhere/sql_loader/control.ctl log=sf1customer.log
and get sqlldr: not found
I don't have much experience with Docker, but my research leads to me to believe that SQL *Loader does not come with the docker image. However, I do not know how to extend the image or where exactly I would call SQL *Loader even if I did. I am on a Ubuntu server and any help would be appreciated.
SQL*Loader is in the image - but the docker container is separate from your host OS, so ubuntu doesn't know any of the files or commands inside it exist. Any commands inside the container should be run as docker commands. If you try this, it should connect to your running container and print the help page:
docker exec -ti oracle19c sqlldr
Since you're running this command on the docker container, sqlldr doesn't have access to any of your host OS's files unless you specifically granted them to the container. But good news - when you started the database with docker run, that's what the -v /opt/oracle:/u01/oracle part of the command did - it mapped /opt/oracle on your Ubuntu filesystem to /u01/oracle in the docker container. So any files that you put in /opt/oracle will be available in the container under /u01/oracle.
So you'll need to do a couple things:
Your control.ctl file, log file, and whatever data file you're using need to be accessible to the container. Either move them to /opt/oracle or shutdown your database container and restart it with something like -v /home/userhere/sql_loader:/u01/oracle in the command.
You might also need to edit your control.ctl file to make sure that it doesn't reference any file paths on your host OS. Either use relative paths (./myfile.csv) or absolute paths with the container's filesystem (/u01/oracle/myfile.csv)
Now you should be able to run sqlldr on the container, and it should be able to access your data files.
docker exec -ti oracle19c sqlldr userid=system control=/u01/oracle/control.ctl log=/u01/oracle/sf1customer.log
Edit: Oh, I should mention - as an alternative, if you download and install the Oracle Instant Client in Ubuntu, you could run sqlldr locally in Ubuntu, and connect to the docker container over the network as a "remote" database:
sqlldr system#localhost:1521/orclpdb1 control=/home/userhere/sql_loader/control.ctl log=sf1customer.log
That way you don't have to move your files anywhere.
From windows, I connected to Postgres Docker container from the local machine. But I can't see the tables that are existed in postgres container. The data is not replicating locally. I followed this tutorial
for running the postgres container on windows.
I managed to create the tables from dump file.
$ docker volume create --name postgres-volume
$ docker run -p 5432:5432 --name postgres_db -e POSTGRES_PASSWORD=password -v postgres-volume:/var/lib/postgresql/data -d postgres
$ docker exec -it <container-id> bash -c "pg_dump -h <source-url> -U postgres -d postgres > /tmp/dump.sql"
$ docker exec -it <container-id> bash -c "psql -f /tmp/dump.sql -U postgres -d postgres"
Any help, appreciated.
Containers
Containers are meant to be an isolated instance of a program/service. They are isolated both from the host and subsequent spawns of the same image. They start off in an isolated island, with nothing in it (that it didn't bring itself). Any data they generate is lost upon their death. They are, also, completely oblivious to any data on the host (for now). But, sometimes, we want their data to be persistent or "inject" our own data each time they start up. Such as your case with PostgreSQL. We want PostgreSQL to have our schema available each time it starts up. And, it would also be great if it retained any changes we made or data we loaded.
Docker Volumes
Enter docker volumes. It is a good method to manage persistent storage for containers. They are meant to be mounted in containers and let them write their data (or read from prior instances) which will not be deleted if the container instance is deleted. Once you create a volume with docker volume create myvolume1, it'll create a directory in /var/lib/docker/volumes/ (on windows it'll be another default. Can be changed). You never have to be aware of the physical directory on your host. You only need be aware of the volume name myvolume1 (or whatever name you choose it to have).
Containers with persistent data (docker volumes)
As we said, containers, by default, are completely isolated from the host. Specifically its filesystem, too. Which means, when a container starts up, it doesn't know what's on the host's filesystem. And, when the container instance is deleted, the data it generated during its life perishes with it.
But, that'll be different if we use docker volumes. Upon a container's start-up, we can mount within it data from "outside". This data can either be the docker volume we spoke of earlier or a specific path we want (such as /home/me/somethingimport which we manage ourselves). The latter isn't a docker volume but works just the same.
Tutorial
The tutorial you linked talks about mounting both a path and a docker volume (in separate examples). This is done with the -v flag when you execute docker run. Because using docker on windows, there is an issue with permissions to the PostgreSQL data directory on the host (which is mounted in the container), they recommend using docker volumes.
This means you'll have to create your schema and load any data you need after you used a docker volume with your instance of PostgreSQL. Subsequent restarts of the container must use the same docker volume.
docker volume create --name postgres-volume
docker run -p 5432:5432 --name postgres_db -e POSTGRES_PASSWORD=password -v postgres-volume:/var/lib/postgresql/data -d postgres
From the tutorial
These are the two important lines. The first creates creates a docker volume and the second starts a fresh PostgreSQL instance. Any changes you make to that instance's data (DML DDL), will be saved in the docker volume postgres-volume. If you've previously spun up a container (for example, PostgreSQL) that uses that volume, it'll find the data just as it was left last time. In other words, what makes the second line a fresh instance is the fact that the docker volume is empty (it was just created). Subsequent instances of PostgreSQL will find the schema+data you loaded previously.
I migrated from Linux to Windows and tried to setup a postgres container with a mounted directory (copied from my Linux install) containing the database.
This does not work.
Windows mounts are always owned by root
Postgres does not run under root
How to get this unholy combination to work?
You don't provide much details so it is difficult to tell what actually went wrong. However there is a known issue with Postgres setup on Windows Docker using a windows mount for database data files. In that case, running docker logs will show something along the following lines
waiting for server to start....FATAL: data directory "/var/lib/postgresql/data" has wrong ownership
HINT: The server must be started by the user that owns the data directory.
stopped waiting
pg_ctl: could not start server
Unfortunately there is no way to overcome this issue so you cannot use Windows mount, see Postgres Data has wrong ownership. You may use docker volumes in order to make database data indipendent from docker postgres container, using the following commands
docker create -v /var/lib/postgresql/data --name PostgresData alpine
docker run -p 5432:5432 --name yourPostgres -e POSTGRES_PASSWORD=yourPassword -d --volumes-from PostgresData postgres
You may find a more thoroughful explanation at Setup Postgresql on Windows with Docker
I am using docker on windows. With the use of kitematic, I have created an ubuntu container. This ubuntu image has postgresql installed on it.
Wondering if there is any possibility to access the postgres configuration files available in the container from the host (windows machine)?
Where exactly does the container store its file system on the host machine?
I hope it would be part of image file with format VMDK.
Please correct me if I'm wrong.
Wondering if there is any possibility to access the postgres configuration files available in the container from the host (windows machine)
That is not how Docker would allow you to modify a file in a container.
For that, you should mount a host (Windows) folder when starting (docker run -v) your container.
See "Mount a host directory as a data volume"
docker run -d -P --name web -v /c/Users/<myACcount>/src/webapp:/opt/webapp training/webapp python app.py
Issue 247 mentions ~/Library/Application Support/Kitematic for App data, and ~/Kitematic "for easy access to volume data".