simpledb | 自己实现一个简单的DB 自己实现一个简单的DB 自己实现数据库（3）BufferPool | Database library

by happyer Java Version: Current License: No License

X-Ray Key Features Code Snippets Community Discussions(10)Vulnerabilities Install Support

kandi X-RAY | simpledb Summary

simpledb is a Java library typically used in Database, MongoDB applications. simpledb has no bugs, it has no vulnerabilities and it has low support. However simpledb build file is not available. You can download it from GitHub.

simpledb

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Quality

Security

License

Reuse

Support

simpledb has a low active ecosystem.

It has 45 star(s) with 3 fork(s). There are 1 watchers for this library.

It had no major release in the last 6 months.

simpledb has no issues reported. There are 2 open pull requests and 0 closed requests.

It has a neutral sentiment in the developer community.

The latest version of simpledb is current.

Quality

simpledb has 0 bugs and 0 code smells.

Security

simpledb has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

simpledb code analysis shows 0 unresolved vulnerabilities.

There are 0 security hotspots that need review.

License

simpledb does not have a standard license declared.

Check the repository for any license declaration and review the terms closely.

Without a license, all rights are reserved, and you cannot use the library in your applications.

Reuse

simpledb releases are not available. You will need to build from source code and install.

simpledb has no build file. You will be need to create the build yourself to build the component from source.

simpledb saves you 18820 person hours of effort in developing the same functionality from scratch.

It has 37187 lines of code, 3198 functions and 383 files.

It has medium code complexity. Code complexity directly impacts maintainability of the code.

Top functions reviewed by kandi - BETA

kandi has reviewed simpledb and discovered the below as its top functions. This is intended to give you an instant insight into simpledb implemented functionality, and help decide if they suit your requirements.

Builds a subtree .
Returns an iterator of sub - plan for the given table .
Parse a query into a logical plan
Convert a file into an output file .
Compute cost and cost card of a subplan .
Splits a leaf page into two leaf pages .
Inserts an entry in the table .
Convert a file .
Truncate the log .
Converts an array of BTreeEntries into a byte array .

Get all kandi verified functions for this library.

simpledb Key Features

No Key Features are available at this moment for simpledb.

simpledb Examples and Code Snippets

No Code Snippets are available at this moment for simpledb.

Community Discussions

Trending Discussions on simpledb

AWS DynamoDB Partition Key Design

Best strategy to archive specific records from RDS to a cheaper storage in AWS

android.database.sqlite.SQLiteException: no such table: SimpleTable (code 1 SQLITE_ERROR[1]): , while compiling: SELECT * FROM SimpleTable

Unable to run integration test in Intellij Idea for scala project

System.ObjectDisposedException - Using SQL Connection within Using Block

docker-compose can not create user and password for mongodb

docker-compose wait-for.sh fails for waiting mongodb

Persisting a bi-directional One-To-Many Association fails with Eclipse Link 2.7.4

What's the best AWS service to use for a simple database (essentially just a key/value store) shared by a number of different services?

Cannot update field when located by object id, json parse error

QUESTION

AWS DynamoDB Partition Key Design

Asked 2021-Jun-15 at 18:09

I read this answer, which clarified a lot of things, but I'm still confused about how I should go about designing my primary key.

First off I want to clarify the idea of WCUs. I get that WCU is the write capacity of max 1kb per second. Does it mean that if writing a piece of data takes 0.25 seconds, I would need 4 of those to be billed 1 WCU? Or each time I write something it consumes 1 WCU, but I could also write X times within 1 second and still be billed 1 WCU?

Usage

I want to create a table that stores the form data for a set of gyms (95% will be waivers, the rest will be incidents reports). Most of the time, each forms will be accessed directly via its unique ID. I also want to query the forms by date, form, userId, etc..

We can assume an average of 50k forms per gym

Options

First option is straight forward: having the formId be the partition key. What I don't like about this option is that scan operations will always filter out 90% of the data (i.e. the forms from other gyms), which isn't good for RCUs.
Second option is that I would make the gymId the partition key, and add a sort key for the date, formId, userId. To implement this option I would need to know more about the implications of having 50k records on one partition key.
Third option is to have one table per gyms and have the formId as partition key. This seems to be like the best option for now, but I don't really like the idea of having a a large number of tables doing the same thing in my account.

Is there another option? Which one of the three is better?

Edit: I'm assuming another option would be SimpleDB?

...

ANSWER

Answered 2021-May-21 at 20:26

For your PK design. What data does the app have when a user is going to look for a form? Does it have the GymID, userID, and formID? If so, make a compound key out of that for the PK perhaps? So your PK might look like:

Source https://stackoverflow.com/questions/67628589

QUESTION

Best strategy to archive specific records from RDS to a cheaper storage in AWS

Asked 2020-Jul-03 at 16:54

I have the following requirements:

For every deleted record in RDS we need to archive it into somewhere cheaper on AWS.
Reduce storage cost
Not using Glacier
Context oriented (e.g. a file per table)
re-import is not a requirement

I'm not an experienced user with AWS, so I'm still a bit lost among the amount of options it has to offer and I'd like to know if you have more ideas to help me clear it out.

Initial thoughts:

The microservice that deletes the record, might send it to a broker (RabbitMQ for e.g.) and another microservice (let's call it archiver) will listen to it, write into a file, zip and send to S3. This approach has some technical challenges though: in order to make sense create big files, I need to wait the queue to growth a bit, wrap it into a stream and zip inside S3. The transaction control is very weak as well, since file writing and ack on messages are signal based i.e. I'll remove the messages from the broker just after the file is created.
Add a new column to the "archiveble" tables as "deleted (bool)" and run a separate job fetching only those records and saving them into S3. Discarded they don't want the new microservice with access to other's databases.
Following the same approach as in the first item, but instead of save into S3, save into a cheaper database. SimpleDB?

...

ANSWER

Answered 2020-Jul-03 at 16:54

option 1, but instead of rabbitmq, write it to a kinesis firehose and direct that to an s3 location - it doesn't get much cheaper or easier than that.

Source https://stackoverflow.com/questions/62719095

QUESTION

android.database.sqlite.SQLiteException: no such table: SimpleTable (code 1 SQLITE_ERROR[1]): , while compiling: SELECT * FROM SimpleTable

Asked 2020-Apr-23 at 23:03

I have tried all of the solutions I could find and still haven't been able to get around this error. The error occurs in the getNotes() section, in its forth line. Also, the getNote() is currently not doing anything, so you don't need to look at that. I directly copied all code from these youtube tutorials, which I then adapted to my needs.

https://www.youtube.com/watch?v=pa_lghjVQVA&t=933s

Thanks for any help.

...

ANSWER

Answered 2020-Apr-23 at 23:03

I assume that you had been following the video which builds up the Database handling step by step.

I have taken your code, added a Note class so it will compile and played around with it a bit. The code itself works fine, however you had (probably do to incremental changes of the code) deleted the table and it has not been recreated yet. Therefore it will always lead to a crash.

Fortunately this can be solved very easily by:

Either reinstalling the App
Or by incrementing the Database version

If you choose to delete and install the App again, you can reset the Database version to 1.

If you choose to increment the Database version, onUpgrade will be called which will delete the table (if it exists) and then recreate it (by calling onCreate).

As someone already mentioned as a comment, SQL should be handled on Android by using Room nowadays. I understand you are probably just starting out, but once you get better you should definitely check out Room. It makes things a LOT easier.

Hope this solves your issue :)

Source https://stackoverflow.com/questions/61396904

QUESTION

Unable to run integration test in Intellij Idea for scala project

Asked 2019-Aug-21 at 10:39

I am using the following version of Intellij Idea

...

ANSWER

Answered 2019-Aug-20 at 06:11

First make sure it works when running sbt it:test or if you use sub-modules sbt module/it:test

If it doesn't sbt has this great resource: https://www.scala-sbt.org/1.x/docs/Testing.html#Integration+Tests

As a template for a working setup, a build.sbt:

Source https://stackoverflow.com/questions/57557496

QUESTION

System.ObjectDisposedException - Using SQL Connection within Using Block

Asked 2019-Jun-17 at 14:30

System.ObjectDisposedException HResult=0x80131622 Message=Cannot access a disposed object. Object name: 'SQLiteConnection'.
Source=System.Data.SQLite

I've written a simple repository that uses Dapper and DapperExtensions

When trying to retrieve some results, I get this error when using a Usingblock after the method returns to the view model. When replacing the Using block with Open/Close methods of the connection I don't receive an error. I feels like the issue is very simple, but I just don't see it.

My "base" DB repository

...

ANSWER

Answered 2019-Jun-17 at 14:03

You need to iterate the result inside the using block:

Source https://stackoverflow.com/questions/56632829

QUESTION

docker-compose can not create user and password for mongodb

Asked 2019-Jun-15 at 10:16

I am following this mongo's official docker page to configure mongodb to start with authorization enabled along with creating user, password and a database. However, when I spin up docker-compose my nodejs component, it isn't able to connect to mongodb because there are no users created in mongodb side.

docker-compose.yml

...

ANSWER

Answered 2019-Jun-15 at 10:16

I think I found the problem. node application wasn't able to access to mongo because I need to add authSource=admin parameter which points the database keeps user's credentials. It also explained here

So, the final url will be;

mongodb://simpleUser:123456@mongodb:27017/simpleDb?authSource=admin

Source https://stackoverflow.com/questions/56581987

QUESTION

docker-compose wait-for.sh fails for waiting mongodb

Asked 2019-Jun-13 at 13:26

I am trying to set up a docker network with simple nodejs and mongodb services by following this guide, however, when building nodejs it fails because it can't connect to mongodb.

docker-compose.yml

...

ANSWER

Answered 2019-Jun-13 at 12:59

I found the problem which was because of the image node:10 doesn't have nc command installed so it was failing. I switched to image node:10-alpine and it worked.

Source https://stackoverflow.com/questions/56579542

QUESTION

Persisting a bi-directional One-To-Many Association fails with Eclipse Link 2.7.4

Asked 2019-Mar-22 at 09:42

I am trying to persist a simple bi-directional One to many relationship, but with eclipse link 2.7.4 it fails. Below is the sample code..

Department Entity (Parent) ...

ANSWER

Answered 2019-Mar-22 at 09:42

The source object must use the mappedBy attribute to define the mapping.

https://en.wikibooks.org/wiki/Java_Persistence/OneToMany#Example_of_a_OneToMany_relationship_and_inverse_ManyToOne_annotations

Source https://stackoverflow.com/questions/55296159

QUESTION

What's the best AWS service to use for a simple database (essentially just a key/value store) shared by a number of different services?

Asked 2019-Jan-25 at 02:17

We have a number of (micro) services, some as simple as a single lambda function, and some are full RDS apps. One thing that they all need to do is access an foreign ID key mapping. That is, they all are passed a certain type of ID, but need to included the "name" field associated with that ID in their responses. Basically, just a key/value store.

I could build a separate microservice to manage these mappings (and maybe still will), but that also needs the simple database.

My services don't usually get a huge amount of throughput, but I need them to be performant.

I'd like to keep it cheap, and I'd like it to be as low maintenance as possible.

Basically, I'd like something "Serverless" (i.e. doesn't require an ongoing EC2 instance or RDS instance running), fast, and straightforward to access.

I've thought about just having each "key" be an S3 key, with the value being the object, but that's not super performant when I need to access a bunch at a time. (should I look into redshift spectrum? is that way overkill? does it matter if is?)

I know AWS used to offer simpledb, which is probably basically what I'm after. So what would be closest now?

Thanks for your advice!

...

ANSWER

Answered 2019-Jan-25 at 02:00

You can use DynamoDB, RDS or S3, I wouldn't recommend SimpleDB.

As for what's "best" I guess it depends on what are the requirements: "better" or "worse" in what regards? ease of development? latency? availability? regional/multi-region? and etc

Source https://stackoverflow.com/questions/54357901

QUESTION

Cannot update field when located by object id, json parse error

Asked 2019-Jan-06 at 00:45

I have a collection with content:

...

ANSWER

Answered 2019-Jan-06 at 00:32

The line where you call JSON.parse fails because the argument is not a JSON. If you do JSON.stringify({"_id":ObjectId("5c312200508c979b46d21866")}) you'll see that it can't turn that into a string either. The reason being that JSONs can contain strings, booleans, numbers, and arrays. ObjectId("5c312200508c979b46d21866") doesn't resolve to something the browser knows, even though it makes sense in the shell. However, I think if you pass it as a string, it should work as a query for the db.

Source https://stackoverflow.com/questions/54057332

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

No vulnerabilities reported

Install simpledb

You can download it from GitHub.
You can use simpledb like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the simpledb component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .

Support

For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .

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