schema

Scalar DB Schema Tools

This document briefly explains tools used to generate and load database schemas for Scalar DB.

Scalar DB schema generator and loader

Scalar DB schema generator (tools/schema/generator) generates storage implementation specific schema definition and metadata definition for Scalar DB transaction as described here for a given Scalar DB database schema. Scalar DB schema loader (tools/schema/loader) uses the generator to get an implementation specific schema file and load it with a storage implemtation specific loader for a give Scalar DB database schema.

With the above tools, you don't need to think about implementation specific schemas when modeling data for your applications.

Scalar DB schema definition

Scalar DB schema is an abstract schema to define applications data with Scalar DB. Here is a spec of the definition.

REPLICATION FACTOR number ';'

CREATE NAMESPACE namespace_name ';'

create_table_statement ::=  CREATE [TRANSACTION] TABLE namespace_name'.'table_name  
                            '('   
                                column_definition
                                ( ',' column_definition )*
                            ');'
column_definition      ::=  column_name data_type [key_definition]
data_type              ::=  BIGINT | BLOB | BOOLEAN | DOUBLE | FLOAT | INT | TEXT 
key_definition         ::=  PARTITIONKEY | CLUSTERINGKEY 

REPLICATION is a global command for replication factor. All the namespaces defined in the same file will have the specified replication factor.

CREATE NAMESPACE is a command to define namespaces. CREATE [TRANSACTION] TABLE is a command to define tables. The grammar for defining tables is as stated above. If you add TRANSACTION keyword, the table is treated as transaction capable, and addtional metadata and coordinator namespace are added. please see this for more information about the metadata and the coordinator.

Install & Build

Before installing, please install and setup golang. Then, make will download the required packages and build generator and loader.

$ cd /path/to/scalardb/tools/schema
$ make

Use

After defining a schema, please run the command as follows. You don't need --database option as of writing since the only supported database is cassandra.

$ ./loader --help
$ ./loader your-schema-file

You can also generate implementation schema file only.

$ ./generator --help
$ ./generator your-schema-file