The api/db/<dbname>/classes/<struct_no> Resource

The api/db/<dbname>/classes/<struct_no> resource executes the following operations for HTTP GET, POST and DELETE:

• GET: Shows the schema for the specified struct_no
• POST: Writes records to the database
• DELETE: Deletes all records of the specified class

For an overview see page eXtremeDB Web Service Resources

GET

With the REST server started (listening on port 8083), the following http request will display the schema for the specified class:

 
    GET http://localhost:8083/api/db/xsqldb/classes/0
            
     

The response displays the schema for the specified class in the following format:

 
    {
        "schema":

        {
    
            "struct_no": 0,
            "name": "I",
            "flags": 9,
            "flags_s":
            [
                "MCO_DICT_SI_CLASS",
                "MCO_DICT_SI_LIST"
            ],
            "class_code": 1,
            "fields"
            [
    
                {
    
                    "field_no": 0,
                    "name": "i",
                    "type": 6,
                    "type_s": "MCO_DD_INT4",
                    "flags": 64,
                    "flags_s":
                    [
                        "MCO_DICT_FI_NULLABLE"
  
                    ]
                },
    
                {
    
                    "field_no": 1,
                    "name": "s",
                    "type": 16,
                    "type_s": "MCO_DD_STRING",
                    "flags": 64,
                    "flags_s":
                    [
                        "MCO_DICT_FI_NULLABLE"
  
                    ]
                },
  
            ],
            "indexes"
            [
    
                {
                    "index_no": 0,
                    "name": "list_index_",
                    "flags": 21,
                    "flags_s":
                    [
                        "MCO_DICT_II_UNIQUE",
                        "MCO_DICT_II_LIST",
                        "MCO_DICT_II_TREE"
                    ],
                    "index": 0,
                    "n_keys_estimate": 0,
                    "fields":
                    [
                    ]
                }
            ],
            "events"
            [
    
            ]    
        }

    }
 

POST

The POST request writes records to the database. All records are written in the context of a single transaction. In case of a failure, the transaction is rolled back and the database is returned to its previous state; and an HTTP error is returned. On success, HTTP status 200 is returned.

The request body is a JSON object. The records are passed as an array of JSON objects, where keys correspond to the records' field names. For example, a single record with an integer field i and a string field s could be inserted with the following JSON object:

 
    {
        "records":
        [
            {
                "i": 3,
                "s": "test"
            }
        ]
    }
     

Field values must be appropriate for the field types in the database. The web service does not attempt to implicitly cast JSON strings to integer fields, or vice versa. Floating-point values are likewise not rounded to integers. The following are the JSON formatting rules for eXtremeDB data types:

• Scalar integer and floating point values: JSON numerics
• Date and time values: timestamps as JSON numerics
• Boolean values: JSON true or false literals
• ASCII fixed- and variable-length strings: JSON strings
• Wide and double-byte (wchar, nchar) strings: JSON hex-encoded strings (e.g. "7400650073007400" for string "test" when encoded using the UTF-16-LE encoding)
• Fixed- and variable-length binary: JSON hex-encoded strings (e.g. "0a0b0c0d")
• Blobs: JSON hex-encoded strings
• Structures: JSON objects with keys for field names, just like class records
• Arrays and vectors: JSON arrays: [1, 2, 3]
• Sequences: JSON arrays: [1, 2, 3]

For example, consider the following table:

     
    CREATE TABLE T4(pk INTEGER PRIMARY KEY, str STRING, bin BINARY(3), 
        arr ARRAY(INTEGER), seq SEQUENCE(CHAR(4)), b BOOLEAN);
         

The following request inserts 2 records (note that omitted fields are stored as nulls):

 
    POST http://localhost:8083/api/db/xsqldb/classes/3
    {
        "records":
        [
            {
                "pk":1, "str": "string1", "bin": "010203", "arr": [1,2,3,4], 
                "seq": ["AAAA", "BBB", "CC", "D"], "b": false
            },
            {
                "pk":2, "str": "string2", "b": true
            }
        ]
    }
     

DELETE

The DELETE request deletes all records of the specified class. For example, the following request deletes all objects of the class with class_code = 3:

 
    DELETE http://localhost:8083/api/db/xsqldb/classes/3
     

On success, the following is returned:

 
    200 OK