# CSV Integration

> Learn how to define CSV formats and mappings in Taxi

Source: https://taxilang.org/docs/other-api-specs/csv

## Overview

Taxi provides CSV format support through model annotations, enabling:
- CSV reading and writing with semantic types
- Configurable delimiters, headers, and value handling
- Column name mapping

## Declaring CSV Models

Add the `Csv` annotation to models that represent CSV data:

```taxi
> import com.orbitalhq.formats.Csv

> @Csv
  model Person {
     firstName: FirstName inherits String
     lastName: LastName inherits String
     age: Age inherits Int
  }
```

## Configuration Options

The `Csv` annotation supports several configuration parameters:

```taxi
> import com.orbitalhq.formats.Csv

> @Csv(
>   delimiter = "|",
>   nullValue = "NULL",
>   firstRecordAsHeader = true,
>   containsTrailingDelimiters = false,
>   quoteChar = "\""
> )
  model Person {
     firstName: FirstName inherits String
     lastName: LastName inherits String
     age: Age inherits Int
  }
```

### Available Options

| Parameter                  | Description                        | Default |
|----------------------------|------------------------------------|---------|
| delimiter                  | Character separating fields        | `,`     |
| firstRecordAsHeader        | Use first record as column headers | `true`  |
| nullValue                  | String to interpret as null        |         |
| containsTrailingDelimiters | Whether rows end with delimiter    | `false` |
| quoteChar                  | Character for quoting fields       | `"`     |

## Column Mapping

### Default Mapping
By default, field names in the model are used to match CSV column names:

```taxi
model Person {
   // Matches CSV column "firstName"
   firstName: FirstName inherits String
   
   // Matches CSV column "lastName" 
   lastName: LastName inherits String
}
```

### Legacy Column References

> **Warning: Deprecated**
>
> Using the `by column` tag is deprecated. Field names in the model are now used to match columns.

For backward compatibility, explicit column mapping is supported but discouraged:

```taxi
   model Person {
>    firstName: FirstName by column("fName")  // Maps to CSV column "fName"
   }
```