Cindex is a easy to use csv indexer with a simple SQL-like query support.
Cindex is not intended for heavy database indexing but for simple in-memory querying. Use other databases interaction layer if you're using big chunks of csv files.
```toml [dependencies] cindex = "*" # Use the latest version if possible
```
```rust use std::fs::File; use cindex::{Indexer, CsvType, Predicate, Query, OutOption, Operator};
let mut indexer = Indexer::new();
// Add table without types // Default types for every columns are "Text" indexer.addtablefast( "table1", File::open("test.csv").expect("Failed to open a file") ).expect("Failed to add table");
// Add table with column types indexer.addtable( "table2", vec![CsvType::Text, CsvType::Text], "id,address 10,110-2222".asbytes() ).expect("Failed to add table");
// Add table from stdin let stdin = std::io::stdin(); indexer.addtablefast( "table3", stdin.lock() ).expect("Failed to add table");
// Indexing
// Create query object and print output to terminal let query = Query::from_str("SELECT a,b,c FROM table1 WHERE a = 10"); indexer.index(query, OutOption::Term).expect("Failed to index a table");
// Use raw query and yield output to a file indexer.index_raw( "SELECT * FROM table3 WHERE id = 10", OutOption::File(std::fs::File::create("out.csv") .expect("Failed to create a file")) ).expect("Failed to index a table");
// Use builder pattern to construct query and index a table let query = Query::empty("table2") .columns(vec!["id", "address"]) .predicate(Predicate::new("id", Operator::Equal) .args(vec!["10"]) ) .predicate(Predicate::build() .column("address") .operator(Operator::NotEqual) .raw_args("111-2222") );
let mut acc = String::new(); indexer.index(query, OutOption::Value(&mut acc)) .expect("Failed to index a table");
// Always use unix newline for formatting indexer.alwaysuseunix_newline(true); ```
Cindex's query syntax is similar to SQL but has some small differences.
```SQL /* Select everythig from given table*/ SELECT * FROM table1
/* Select everything from given table and order by column with descending order*/ SELECT * FROM table1 ORDER BY col1 DESC
/* Same with previous commands but map header result */ SELECT * FROM table1 ORDER BY col1 DESC HMAP newh,newh2,new_h3
/* -> Previous query result header with underbar substituted with whitespaces new h,new h2,new h3 <-- Content goes here --> */
/* Select given columns from table where column's value is equal to given condition and also other column's value matches regex expression */ SELECT col1,col2 FROM table1 WHERE col1 = 10 AND col2 LIKE ^start
/* There is a flag syntax which changes query behaviour*/ SELECT * FROM table_name FLAG PHD SUP
/* In this case each flag does next operation - PHD (PRINT-HEADER) : Print header in result output - SUP (SUPPLEMENT) : Enable selection of non-existent column with empty values */ ```
Supported WHERE operations are
```
=
<= < = != IN BETWEEN LIKE ( with regeular expression ) ```