Apache Calcite
ANTLR
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Apache Calcite | ANTLR | |
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28 | 17 | |
4,352 | 16,331 | |
1.8% | 1.4% | |
9.0 | 8.5 | |
6 days ago | 6 days ago | |
Java | Java | |
Apache License 2.0 | BSD 3-clause "New" or "Revised" License |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
Apache Calcite
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Data diffs: Algorithms for explaining what changed in a dataset (2022)
> Make diff work on more than just SQLite.
Another way of doing this that I've been wanting to do for a while is to implement the DIFF operator in Apache Calcite[0]. Using Calcite, DIFF could be implemented as rewrite rules to generate the appropriate SQL to be directly executed against the database or the DIFF operator can be implemented outside of the database (which the original paper shows is more efficient).
[0] https://calcite.apache.org/
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Apache Baremaps: online maps toolkit
Yes, planetiler rocks and the memory mapped collections enabled us to remove our dependency to rocksdb.
From my perspective, planetiler started as an effort to generate vector tiles from the OpenMapTile schema as fast as possible (pbf -> mvt). By contrast, Baremaps started as an effort to create a new schema and style from the ground up. In this regard, having a database (pbf -> db <- mvt) enables to live reload changes made in the configuration files. The database has a cost, but also comes with additional advantages (updates, dynamic data, generation of tiles at zoom levels 16+, etc.).
That being said, I think the two projects overlap and I hope we will find opportunities to collaborate in the future. For instance, whereas PostgreSQL is still required in Baremaps, I recently ported a lot of the ST_ function of Postgis to Apache Calcite with the intent to execute SQL on fast memory mapped collection.
https://github.com/apache/calcite/blob/main/core/src/main/ja...
A planet wide import in Postgis currently takes about 4 hours with the COPY API (easy to parallelize) followed by about 12 hours of simplification in Postgis (not easy to parallelize). I will try to publish a detailed benchmark in the future.
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How to manipulate SQL string programmatically?
Use a SQL Parser like sqlglot or Apache Calcite to compile user's query into an AST.
- Can SQL be used without an RDBMS?
- Apache Calcite
- Want to contribute more to open source projects.
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CITIC Industrial Cloud — Apache ShardingSphere Enterprise Applications
The SQL Federation engine contains processes such as SQL Parser, SQL Binder, SQL Optimizer, Data Fetcher and Operator Calculator, suitable for dealing with co-related queries and subqueries cross multiple database instances. At the underlying layer, it uses Calcite to implement RBO (Rule Based Optimizer) and CBO (Cost Based Optimizer) based on relational algebra, and query the results through the optimal execution plan.
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Postgres wire compatible SQLite proxy
Awesome to see work in the DB wire compatible space. On the MySQL side, there was MySQL Proxy (https://github.com/mysql/mysql-proxy), which was scriptable with Lua, with which you could create your own MySQL wire compatible connections. Unfortunately it appears to have been abandoned by Oracle and IIRC doesn't work with 5.7 and beyond. I used it in the past to hack together a MySQL wire adapter for Interana (https://scuba.io/).
I guess these days the best approach for connecting arbitrary data sources to existing drivers, at least for OLAP, is Apache Calcite (https://calcite.apache.org/). Unfortunately that feels a little more involved.
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Launch HN: Hydra (YC W22) – Query Any Database via Postgres
For anyone interested, Apache Calcite[0] is an open source data management framework which seems to do many of the same things that Hydra claims to do, but taking a different approach. Operating as a Java library, Calcite contains "adapters" to many different data sources from existing JDBC connectors to Elasticsearch to Cassandra. All of these different data sources can be joined together as desired. Calcite also has it's own optimizer which is able to push down relevant parts of the query to the different data sources. However, you get full SQL on data sources which don't support it, with Calcite executing the remaining bits itself.
Unfortunately, I would not be too surprised if Calcite was found to be less performance-optimized than Hydra. That said, there are users of Calcite at Google, Uber, Spotify, and others who have made great use of various parts of the framework.
[0] https://calcite.apache.org/
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Anyone know of any software that can help in designing then outputting to various database
Abstraction Layer - You can use something like Calcite to abstract out your data storage. https://calcite.apache.org/
ANTLR
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Library to parse slash commands with validation?
antlr https://github.com/antlr/antlr4
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How should I prepare for AI-driven changes in the industry as a Software Engineering Manager
Download the ANTLR jar from https://www.antlr.org/download/antlr-4.9.2-complete.jar Add the ANTLR jar to your project's classpath. Install the ANTLR Kotlin target by following the instructions at https://github.com/antlr/antlr4/blob/master/doc/targets/Kotlin.md Next, you'll need a Perl grammar file for ANTLR:
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ELI5- Why can’t regex parse HTML?
Write a context-free grammar for it, commonly written in Backus Naur Form, and use that to write a parser. There are tools named "parser generators" like antlr4 that can automatically convert a BNF grammar into a parser.
- Error "ImportError: No Module named antlr4
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MASSIVE help needed on this, using ANTLR4 on Ubuntu and it keeps giving this error when trying to make a parse tree… (it should show up in another window but it gives this instead) I don’t know what to do 😭
Tutorial on using it in Java: https://www.baeldung.com/java-antlr Github project itself with docs and examples: https://github.com/antlr/antlr4
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Scripting language for Java
Depending on how complex your expressions are, you might consider using something like antlr and writing your own parser for it. Setting up something to handle math and string operations wouldn’t be very hard and then you can control the syntax however you like. You can use a visitor and visit each node in the syntax tree and return the result of each sub-expression.
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SQLite Internals: How the Most Used Database Works
> ...than it would be to learn the exact syntax and quirks and possibly bugs of someone else's implementation...
Yup. Also, having deep knowledge of the language is required.
SQLite's grammar is neat. Creating a compatible parser would make a fun project. Here's a pretty good example: https://github.com/bkiers/sqlite-parser (Actual ANTLR 4 grammar: https://github.com/bkiers/sqlite-parser/blob/master/src/main... )
Postgres, which tries to be compliant with the latest standards, however...
SQL-2016 is a beast. Not to mention all the dialects.
I'm updating my personal (soon to be FOSS) grammar from ANTLR 3 LL(k) to ANTLR 4 ALL().
I've long had a working knowledge of SQL-92, with some SQL-1999 (eg common table expressions).
But the new structures and extensions are a bit overwhelming.
Fortunately, ANTLR project has ~dozen FOSS grammars to learn from. https://github.com/antlr/grammars-v4/tree/master/sql
They mostly mechanically translate BNFs to LL(k) with some ALL(). Meaning few take advantage of left-recursion. https://github.com/antlr/antlr4/blob/master/doc/left-recursi...
Honestly, I struggled to understand these grammars. Plus, not being conversant with the SQL-2016 was a huge impediment. Just finding a succinct corbis of test cases was a huge hurdle for me.
Fortunately, the H2 Database project is a great resource. https://github.com/h2database/h2database/tree/master/h2/src/...
Now for the exciting conclusion...
My ANTLR grammar which passes all of H2's tests looks nothing like any of the official or product specific BNFs.
Further, I found discrepancy between the product specific BNFs and their implementations.
So a lot of trial & error is required for a "real world" parser. Which would explain why the professional SQL parsing tools charge money.
I still think creating a parser for SQLite is a great project.
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sqlfluff VS ANTLR - a user suggested alternative
2 projects | 12 Dec 2022
can be used to parse
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Bored CS student in my junior year. Give me something to do! (free plugins)
I already posted here about a project, but I could also use help on Mantle. It's a new command framework powered by ANTLR, if that's something you're interested in.
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ANTLR4
ive been tryng to work with antlr4 and go but it seems that i cant import the runtime, it says that the antlr runtime isnt in the gopath but ive already done go get github.com/antlr/antlr4/runtime/antlr4 and i dont know what to do now, im on windows if anyone knows what to do it would be very helpful. thanks already
What are some alternatives?
Trino - Official repository of Trino, the distributed SQL query engine for big data, formerly known as PrestoSQL (https://trino.io)
JFlex - The fast scanner generator for Java™ with full Unicode support
Presto - The official home of the Presto distributed SQL query engine for big data
lsp-mode - Emacs client/library for the Language Server Protocol
JSqlParser - JSqlParser parses an SQL statement and translate it into a hierarchy of Java classes. The generated hierarchy can be navigated using the Visitor Pattern
zetasql - ZetaSQL - Analyzer Framework for SQL
Apache Spark - Apache Spark - A unified analytics engine for large-scale data processing
sql-parser - A validating SQL lexer and parser with a focus on MySQL dialect.
Apache Drill - Apache Drill is a distributed MPP query layer for self describing data
proleap-cobol-parser - ProLeap ANTLR4-based parser for COBOL