Schema and table semantics

Since the datastore types that MetaModel support are widely different, one might question "what does a schema or a table mean?" for eg. Excel spreadsheets, CSV files etc.

On this page we will answer such questions. In the table below there's a list of MetaModel modules and an explanation of the semantics of schemas and tables.

ModuleSchemaTable
JDBCA database schema, as defined by JDBC.A database TABLE, VIEW or other tabular structure in a schema.
OpenOfficeA database schema, as defined by JDBC.A database TABLE, VIEW or other tabular structure in a schema.
CSVA handle to the CSV file. If the file does not exist, schema will be empty. Always has default schema and virtual information schema.The actual file structure, based on the column name line.
ExcelA handle to the Excel spreadsheet. If the file does not exist, schema will be empty. Always has default schema and virtual information schema.A sheet in the spreadsheet
Fixed widthA handle to the Fixed value width file. Always has default schema and virtual information schema.The actual file structure, based on the column name line.
AccessA handle to the Access file. Always has default schema and virtual information schema.The tables in the Access database file.
dBaseA handle to the dBase file. Always has default schema and virtual information schema.The tables in the dBase database file.
XML (SAX)A handle to the XML file. Always has default schema and virtual information schema.A certain position in the XML tree, defined by a user's xpath expression. Each table also has xpath expressions for each column, which define the values of the rows in a table.
XML (DOM)A handle to the XML file. Always has default schema and virtual information schema.All tables are virtual representations of recurring combinations of XML elements. The actual generation of tables depend on whether you perform manual or automatic "flattening" (denormalization) of tables
MongoDBA MongoDB database.A MongoDB collection with a virtual table model, which represent the properties of the documents in the collection.
Salesforce.comA handle to the web services of SalesforceA type of Salesforce.com SObject.
SugarCRMA handle to the web services of SugarCRMA SugarCRM 'module'.

Semantics of "Create table"

In addition to understanding "what is a table?" it is also useful to know what it means to "create" a table, as it is facilitated by MetaModel 2.0 and onwards.

ModuleCreate table semantics
JDBCIssue a CREATE TABLE statement to the database.
CSVCreate or overwrite the CSV file with a (new) table structure. If multiple files should be created, then create a new CsvDataContext and issue the createTable operation there.
ExcelCreates a new sheet in the Excel spreadsheet.
MongoDBCreates a new collection in the MongoDB database.
CouchDBCreates a new CouchDB database.
POJO (Java objects)Creates a new collection of Java objects (Map based).