> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arc.cdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# dbListColumns

> Lists the columns in a table or view on the database server.

export const siteNameShort = "Arc";

Lists the columns in a table or view on the database server. Depending on your configuration and the target database type, some of these parameters and output attributes might not be relevant.

## Required Parameters

* **driver**: The JDBC driver class name in the cross-platform edition or the ADO.NET provider name in the .NET edition.
* **conn**: The connection string or database URL.
* **table**: The table or view from which to list the columns.

## Optional Parameters

* **schema**: The name of the database schema in which the table resides. The schema is commonly referred to as the *namespace* of a group of tables.
* **catalog**: The catalog in the database server. This is  commonly referred to as the *database*. If you do not provide a value, columns from all catalogs in the database server are returned.

## Output Attributes

* **db:columnname**: The name of the column in the specified table or view.
* **db:datatype**: The SQL data type of the column in the specified table or view.
* **db:columnsize**: The size of the column in the specified table or view.
* **db:iskey**: Boolean (true or false) indicating if the column is the primary key column.
* **db:nullable**: Boolean (true or false) indicating if the column is nullable.
* **db:readonly**: Boolean (true or false) indicating if the column is read-only.
* **db:autoincrement**: Boolean (true or false) indicating if the column is an autoincrement column.

## Example

In this example, the targeted database server is MySQL and the targeted table is `actor`. Notice that there is no `database` parameter in the connection string: if the database is specified in the connection string, the `catalog` parameter is not required. This script writes all the attributes of the target table to an output file.

```xml theme={null}
<!-- Initializing the output item -->
<arc:set attr="output.data" />
<!-- Creating the input db item and the necessary attributes -->
<arc:set attr="db.driver" value="cdata.jdbc.mysql.MySQLDriver" />
<arc:set attr="db.catalog" value="sakila" />
<arc:set attr="db.table" value="actor" />
<arc:set attr="db.conn" value="jdbc:cdata:mysql:server=localhost;port=3306;user=root;password=Password123;"/>

<arc:call op="dbListColumns" in="db" out="results" >
  <!-- adding result data from the operation to an output item that will be pushed out as a file -->
  <arc:set attr="output.data">[output.data]\nColumn Name=[results.db:columnname]\nData Type=[results.db:datatype]\nSize=[results.db:columnsize]\nKey=[results.db:iskey]\nNullable=[results.db:nullable]\nReadOnly=[results.db:readonly]\nAutoInc=[results.db:autoincrement]\n-----</arc:set>
</arc:call>

<!-- setting the filename and pushing the file out --> 
<arc:set attr="output.filename" value="results.txt" />
<arc:push item="output" />
```

Output:

```
Column Name=actor_id
Data Type=SMALLINT UNSIGNED
Size=2
Key=True
Nullable=False
ReadOnly=False
AutoInc=True
-----
Column Name=first_name
Data Type=VARCHAR
Size=45
Key=False
Nullable=False
ReadOnly=False
AutoInc=False
-----
Column Name=last_name
Data Type=VARCHAR
Size=45
Key=False
Nullable=False
ReadOnly=False
AutoInc=False
-----
Column Name=last_update
Data Type=TIMESTAMP
Size=19
Key=False
Nullable=False
ReadOnly=False
AutoInc=False
-----
```

You can modify the example above to target other databases as long as the driver is installed on the machine where {siteNameShort} is installed and running. Adjusting this example for .NET involves changing the `driver` and `conn` inputs as follows:

```xml theme={null}
<arc:set attr="db.driver" value="System.Data.CData.MySql" /> 
<arc:set attr="db.conn" value="Server=localhost;Database=sakila;UID=root;Password=Password123;"/>
```