OJAI Query Syntax

See Query with --query to learn about how to use this syntax in HPE Ezmeral Data Fabric Database shell.

An OJAI query can include the following components:

• Projection
• Condition
• Order by
• Limit
• Offset
• Options

You can specify some or all these components in a query, separating each component with a comma.

OJAI Query Projection

Syntax

"$select":"fieldpath"

"$select":["fieldpath1","fieldpath2",...]

Description

The projection is the list of field paths to select in your query. You can specify a single field path or multiple. When specifying multiple, use an array notation to list the field paths.

See JSON Document Field Paths for more information about the syntax of different JSON document field paths.

Examples

Single field path:

"$select":"a.c.d"

Multiple field paths:

"$select":["a.c.d", "a.c.e", "m[0]"]

OJAI Query Condition

Syntax

"$where":OJAIQueryCondition

Description

The condition filters your query result. See OJAI Query Condition Syntax for more information about the syntax of an OJAIQueryCondition.

Example

If you have the following condition:

(a.b.[0].boolean == false && (a.c.d != 5 || a.b[1].decimal > 1 || a.b[1].decimal < 10))

This is the OJAI JSON syntax for the condition:

"$where":{
    "$and":[
        {"$eq":{"a.b[0].boolean":false}},
        {"$or":[
            {"$ne":{"a.c.d":5}},
            {"$gt":{"a.b[1].decimal":1}},
            {"$lt":{"a.b[1].decimal":10}}
            ]
        }
    ]
} 

OJAI Query Order By

Syntax

"$orderby":"fieldpath"

"$orderby":{"fieldpath":"order"}

"$orderby":[fieldpath1,fieldpath2,...]

"$orderby":[{"fieldpath1":"order"},{"fieldpath2":"order"},...]

Description

The order by specifies the field paths on which to sort your query result. You can specify a single field path or multiple. When specifying multiple, use an array notation to list the field paths. For each field path, you can optionally specify an order of either asc or desc. Both order keywords are case insensitive. The default is asc. When specifying an order, enclose the fieldpath and order with curly braces.

Examples

Order on a single field path in the default asc order:

"$orderby":"a.c.e"

Order on a single field path in the desc order:

"$orderby":{"a.c.e":"desc"}

Order on two field paths, where the second specifies a desc order:

"$orderby":["a.c.d",{"a.c.e":"desc"}]

OJAI Query Limit

Syntax

"$limit":positive-integer

Description

The number of documents to return from the query.

Example

Return only ten documents:

"$limit:10

OJAI Query Offset

Syntax

"$offset":positive-integer

Description

The number of documents to skip before returning results to the client. The offset value has a direct effect on query time; as the offset value increases, query time also increases.

Example

Process the query and skip the first five documents in the result set before returning the results to the client.

"$offset":5

OJAI Query Options