AssertID check id is empty err := AssertID(id) .

AssertObject return error if ctx/obj has problem err := AssertObject(ctx, Sample) .

ASC mean order by asc .

CounterDateLevel field in shard .

CounterTime field in shard .

DESC mean order by DESC .

HierarchyDay define day period .

HierarchyHour define hour period .

HierarchyMonth define month period .

HierarchyTotal define total period .

HierarchyYear define year period .

MetaID field in shard .

MetaN field in shard .

BaseClient represent object stored in document database .

BaseQuery represent a query in document database .

Entity a class that has id .

Model is class with AccountID and UserID .

Batch define batch operation .

Client define how to connect and manipulate document database .

Coder is a collection of documents (shards) to realize code with high frequency.

Counter is a collection of documents (shards) to realize counter with high frequency.

Object is any defined object in a database that is used to store or reference data .

Query represent query public method.

Serial can generate serial Sequence in low frequency.

Transaction define transaction operation .

BatchFunc define a batch function .

Hierarchy define date hierarchy .

TransactionFunc define a transaction function .