README.md

pydap.handlers.sql

This handler allows Pydap to serve data from any relational database supported by SQLAlchemy. Each dataset is represented by a YAML file (with extension .sql) that defines the database connection, variables and other associated metadata. Here's a simple example:

# These parameters are mandatory; they define the database to connect and the
# table holding the data. Note that table might be a selection.
database:
    dsn: 'sqlite:///simple.db'
    table: test

# This is just metadata defining the dataset; no attributes are required.
dataset:
    NC_GLOBAL:
        history: Created by the Pydap SQL handler
        dataType: Station
        Conventions: GrADS

    contact: [email protected]
    name: test_dataset
    owner: Roberto De Almeida
    version: 1.0
    last_modified: !Query 'SELECT time FROM test ORDER BY time DESC LIMIT 1;'

# This is just metadata defining the sequence; no attributes are required.
sequence:
    name: simple
    items: !Query 'SELECT COUNT(id) FROM test'

# Each variable must have an attribute called `col`, referencing the column;
# all other are optional.
_id:
    col: id
    long_name: sequence id
    missing_value: -9999

lon:
    col: lon
    axis: X
    grads_dim: x
    long_name: longitude
    units: degrees_east
    missing_value: -9999
    global_range: [-180, 180]
    valid_range: !Query 'SELECT min(lon), max(lon) FROM test'

lat:                                                                            
    col: lat                                                                    
    axis: Y                                                                     
    grads_dim: y                                                                
    long_name: latitude                                                         
    units: degrees_north                                                        
    missing_value: -9999                                                        
    global_range: [-90, 90]                                                     
    valid_range: !Query 'SELECT min(lat), max(lat) FROM test'                   
                                                                                
time:                                                                           
    col: time                                                                   
    axis: T                                                                     
    grads_dim: t                                                                
    long_name: time                                                             
    missing_value: -9999                                                        
                                                                                
depth:                                                                          
    axis: Z                                                                     
    col: depth                                                                  
    long_name: depth                                                            
    missing_value: -9999                                                        
    units: m                                                                    
                                                                                
temp:                                                                           
    col: temp                                                                   
    long_name: temperature                                                      
    missing_value: -9999                                                        
    units: degc

Note that you can have attributes that read from the database. They should be prefixed by the token !Query.