I know SQLite Data Base is used in mobile devices (Android, iPhone) and it is light, takes only Kb space. Is there any limitation in SQLite? I want to know how they are different.
Every SQL database uses its own implementation of the language that varies slightly. While basic queries are almost universal, there are notable nuances between MySQL, PostgreSQL, Microsoft SQL Server, Oracle Database, etc.
What's particularly notable about SQLite is that unlike all the others mentioned above, this database software doesn't come with a daemon that queries are passed through. This means that if multiple processes are using the database at once, they will be directly altering the data through the SQLite library and making the read / write data calls to the OS themselves. It also means that the locking mechanisms don't deal with contention very well.
This isn't a problem for most applications that where one would think of using SQLite -- the small overhead benefits and easy data retrieval are worth it. However, if you'll be accessing your database with more than one process or don't consider mapping all your requests through one thread, it could be slightly troublesome.
Sqlite is very light version of SQL supporting many features of SQL. Basically is been developed for small devices like mobile phones, tablets etc.
SQLite is a third party ,open-sourced and in-process database engine. SQL Server Compact is from Microsoft, and is a stripped-down version of SQL Server.They are two competing database engines.
SQL is query language. Sqlite is embeddable relational database management system.
Edit : ( Source from following comment on my answer )
Sqlite also doesn't require a special database server or anything. It's just a direct filesystem engine that uses SQL syntax. ( By : Adam Plocher )
Techinically, SQLite is not open-source software but rather public domain. There is no license. ( By : Larry Lustig )
SQL is a query language. SQLite is an embeddable relational database management system.
Unlike other databases (like SQL Server and MySQL) SQLite does not support stored procedures.
SQLite is file-based, unlike other databases, like SQL Server and MySQL which are server-based.
What is SQLite?
SQLite is an open-source, zero-configuration, self-contained, stand-alone, transaction relational database engine designed to be embedded into an application.
Python SQLite can be defined as a C Library developed using ANSI-C, light-weight disc based database; doesn't demand for an extra or any other separate server process.
What are some SQLite characteristic?
SQLite does NOT require a server to run (RDBMS such as MySQL, PostgreSQL, etc., requires a separate server process to operate).
Is self-contained, it requires minimal support from the operating system or external library. This makes SQLite usable in any environment especially in embedded devices like iPhones, Android phones, game consoles, handheld media players.
Does not use any configuration files.
Is ACID-compliant. It means all queries and changes are Atomic, Consistent, Isolated, and Durable, all changes within a transaction take place completely or not at all even when an unexpected situation like application crash, power failure, or operating system crash occurs.
Capable of creating in-memory databases that are very fast to work with.
Uses dynamic types for tables. It means you can store any value in any column, regardless of the data type.
Allows a single database connection to access multiple database files simultaneously.
SQLite & ACID
SQLite guarantees all the transactions are ACID compliant even if the transaction is interrupted by a program crash, operation system dump, or power failure to the computer.
Atomic: a transaction should be atomic. It means that a change cannot be broken down into smaller ones. When you commit a transaction, either the entire transaction is applied or not.
Consistent: a transaction must ensure to change the database from one valid state to another. When a transaction starts and executes a statement to modify data, the database becomes inconsistent. However, when the transaction is committed or rolled back, it is important that the transaction must keep the database consistent.
Isolation: a pending transaction performed by a session must be isolated from other sessions. When a session starts a transaction and executes the INSERT or UPDATE statement to change the data, these changes are only visible to the current session, not others. On the other hand, the changes committed by other sessions after the transaction started should not be visible to the current session.
Durable: if a transaction is successfully committed, the changes must be permanent in the database regardless of the condition such as power failure or program crash. On the contrary, if the program crashes before the transaction is committed, the change should not persist.
Credit Sqlitetutorial.net
The most basic difference between SQLite and SQL is :
SQL is a query language which is used by different SQL databases. It is not a database itself.
SQLite is a database management system itself which uses SQL.
SQL is a database querying language and SQLite is a database (RDBMS) which uses SQL specifications. SQLite can be said as competitor to Microsoft's SQL Server.
The name itself suggests that it is the light version of SQL RDBMS. It is used in most of the small and portable devices like Android and iOS devices.
SQLite: Database Management System (DBMS).
SQL: Structured Query Language is a computer language, used to Create, edit and get data from DBMS via queries.
Related
I'm working on an Android app where we need to migrate from some legacy SQLite code to a Room based implementation. But I've run into a couple of issues & I'm not sure how to solve them.
Environment:
Android 6.0+
SQLite implementation is in one database file
Room implementation is in a separate database file
Both will be in /data/user/0/.../databases/
What sorta works, but is slow:
We have a working test implementation to pull all the legacy SQLite tables' data into Kotlin objects, then do inserts into the Room based tables. But, it's fairly slow for our test cases (about 70 secs for 10k+ rows in at least one table). Real life cases could top 100k rows in at least one table. As far as I can tell, the select is one transaction and the inserts are wrapped in a transaction. So, I don't think it's transaction overhead slowing us down.
What we want to make work:
What I'm hoping to do is use SQLite's attach database and detach commands to load the legacy SQLite database into a Room DB connection. Then, I can do an insert into new_table.table_name select * from old_table.table_name. The actual SQL will be slightly different due to slight schema changes. But, the insert-select pattern will be the basic idea.
I'm using ContextWrapper to get the full database path for the legacy database file. That works fine.
What issues I'm seeing:
When I try to do the attach command, though, I was getting an IllegalStateException with something about not being able to enable/disable write-ahead logging while in a transaction or the db is open. But, the legacy DB is not open or in a transaction at that point.
So, I modified the approach to set the journal mode to TRUNCATE in the Room db connection setup. That allowed me to do the attach command. And the insert-select query seems to work as far as I can tell (I haven't fully tested that yet). BUT, when I tried the detach command, I got a SQLite 1 error about the database being locked.
For reference, my basic code for both above attach approaches is:
roomDb.execSQL("attach database '$fullLegacyDbPath' as old_db")
roomDb.execSQL($insertSelectQuery) // the "INSERT INTO ... SELECT ..." query
roomDb.execSQL("detach old_db")
Any ideas how I make this work (preferably without setting the journal mode to truncate)?
I would like to ask because I am very confused about something.I can't find it nowhere.
Does Firestore
1)support whole operators of SQL SELECT?
2)it doesnt support SQL SELECT?
3)or support a small number of operators SQL SELECT?
which one is true?
I ask that question because I see it somewhere and I didn't remember where.
The issue is I know about firebase a lot.I know and for local database.
I know that when we use firebase we use some SQL or we can create it in the website.
I try search theory about this but I didn't find anything similar to this.
What is your aspect of view?
Firebase is a platform with 18 or so products, so you'll want to clarify which one you're asking about.
Luckily for the sake of its questions, both of the databases in Firebase (Cloud Firestore and the Realtime Database) are NoSQL databases, which (as the name implies) means that they're not SQL databases at all.
Neither Firestore nor Realtime Database supports SQL operators, and in fact they don't support many of the operations you may be familiar with from SQL at all. Common SQL operations, such as projections (SELECT), server-side joins (JOIN), groupings (GROUP BY), and aggregation (COUNT, SUM, etc) are all non-existent in the Firebase (and many other) NoSQL databases.
What both of these databases do bring (and why you'll typically pick them) is:
Direct access from client-side application code, with a server-side security rules model to ensure all access is authorized.
Realtime synchronizes of changes from the database to the client, meaning you don't have to poll the server for updates.
Massive scalability (Firestore more on the number of concurrent reads, Realtime Database more on the smaller writes).
If those are what drew you to Firebase, I recommend learning more about it by reading the documentation, and/or taking a tutorial/codelab. If you were hoping to find a free cloud-hosted SQL database, Firebase is not that - and you're probably better off looking elsewhere.
I'm currently trying to import ~300.000 lines saved in a file.sql.
After reading few forums, few posts stackoverflow, I found two main solutions :
Use my own database with android (https://blog.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications)
Use a csv file or sql file and import it with a transaction
How to populate a large sqlite database on first run
https://www.sqlite.org/cvstrac/wiki?p=ImportingFiles
Inserting large amount of data into android sqlite database?
What is the best solution, considering the performance aspect, the evolvment aspect (volumetry), the best practises on Android...?
In the perfect case, can I have a example ?
I'm using ORMlite libray, and classic DatabaseHelper methods like :
onCreate => to import my data
onUpgrade => to do my migrations scripts (https://riggaroo.co.za/android-sqlite-database-use-onupgrade-correctly/)
Edit : The database is used for the operations of read-write, and is synchronized with a primary server, in order to obtain and send the changes (using Flatbuffer).
The reason for which I need to import these data is because the synchronization dating of a timestamp 0 (all the lines contained in the base of data of the backend server) is too long at the level of the time.
What is the best solution, considering the performance aspect
Shipping a database in assets, and using SQLiteAssetHelper to install it as needed, should be much faster than anything involving executing database transactions.
volumetric evolution about data. the amount of my line (in file.sql), will grow.
Shipping a database in assets will be faster for deploying the app to a new user.
For existing users, neither of your approaches works, and you will need to craft your own code to blend:
Your new data that you want to ship with the app
The old data that you already shipped and have on the user's device
The data that is on the user's device that shipped with neither the original nor the updated app (e.g., data from a server, data entered by the user)
Not sure, if this is important: app is written with react-native.
Question is about both iOS and android apps.
I have a static database, which contains currently ~9000 rows, each row contains 45 columns and about 280 letters total in it. So, basically, database is relatively small. I'll need to perform pattern search (equivalent of ILIKE in Postgres) and sorting based on misc columns with numeric values. No insertions, no modifications, no relations with other "Tables" required.
Should i write nodejs server, instantiate PG database, connect app through web-socket and start querying data from pg, or should i just somehow create local database in app and search through it right in app? The local db is way simpler but I'm worry about performance. If nothing wrong with performance, then what if the database will grow to 15000? 50000?
If the database can be local and there's no need for it to ever be persisted on servers, then you should probably explore Realm. I have not heard of how it great it performs with a lot of data but it acts as a database engine in your phone and has indexing as well.
I am trying to develop this android application whose database is not stored in the device but on a server. To use sqlite database I need to use android.database.sqlite; and I haven't made much use of android.database package. I went through the documentation site but it did not state clearly if it's possible can store my sqlite database file on server and invoke methods to access it from there. What should I do?
SQLite is not an ideal database to use on a server. The andriod.database.sqlite package is going to have resources for dealing with sqlite specifically, where the android.database package is going to have generic database resources, not specific to sqlite.
For using sqlite on a server, first bear in mind that concurrent connections are a big no-no... sqlite is not designed to handle them.
If I still felt I had to do this, I'd probably look at creating an adapter on the server which would accept requests from the application, then use the android.database.sqlite package on the server, as it's local per the scope there (as sqlite is designed for).
https://www.sqlite.org/serverless.html