To use GLORP to correctly map between an RDBMS and Smalltalk objects, you need to do the following:

• Create a descriptor class. You do this by subclassing Glorp.DescriptorSystem. You then add your descriptions (see below) as methods to this class.
• A table model. This describes how the table in the database should look like. The naming convention is #tableForTABLENAMEINUPPERCASE:. For example:

  tableForMYTABLE: aTable
      (aTable createFieldNamed: 'id' type: platform sequence) bePrimaryKey.
      aTable createFieldNamed: 'text' type: platform text.
      aTable createFieldNamed: 'size' type: platform int4.
  

• A mapping descriptor. This describes how the fields in your database map to instance variables of your objects. The naming convention here is #descriptorForYourObjectClass.

  descriptorForMyObject: aDesc
      | t |
      t := self tableNamed: 'mytable'.
      aDesc table: t.
      (aDesc newMapping: DirectMapping) from: #id to: (t fieldNamed: 'id').
      (aDesc newMapping: DirectMapping) from: #text to: (t fieldNamed: 'text').
      (aDesc newMapping: DirectMapping) from: #size to: (t fieldNamed: 'size').
  

• A class model (Optional for simple cases, this can be inferred from the other descriptions). It needs to be called classModelForYourClassName.

  classModelForMyObject: model
      model
          newAttributeNamed: #id;
          newAttributeNamed: #text;
          newAttributeNamed: #size;
  

• Declare all tables used. The method #allTableNames is supposed to return a Collection of all your tables:

  allTableNames
      ^ #( 'mytable' )
  

• Declare all classes used. The method #constructAllClasses should list all classes used as in:

  constructAllClasses
      ^ (super constructAllClasses)
          add: MyClass;
          yourself
  

You can now instruct glorp to build the tables in the database according to your description. sess is a GlorpSession.

createSchema
    "Execute me to create a fresh schema"

    "First, get a GlorpSession somehow --> sess"
    ...
    self dropTables: sess.
    self createAllSequences: sess.
    self createAllTables: sess.


createAllSequences: sess
    sess system platform areSequencesExplicitlyCreated 
        ifTrue: 
            [sess system allSequences do: 
                [:each | 
                    sess accessor createSequence: each
                    ifError: [:error | Transcript show: error messageText]]]


createAllTables: sess 
    sess system allTables do: 
        [:each | 
            sess accessor createTable: each
            ifError: [:errorx | Transcript show: errorx messageText]].
    sess system allTables do: 
        [:each | 
            sess accessor createTableIndexes: each
            ifError: [:errorx | Transcript show: errorx messageText]].
    sess system allTables do: 
        [:each | 
            sess accessor createTableFKConstraints: each
            ifError: [:errorx | Transcript show: errorx messageText]]

connectToDatabase
    | login accessor sess |
    login := (Login new)
        database: PostgreSQLPlatform new;
        username: 'dbusername';
        password: 'dbpassword';
        connectString: 'localhost_databasename'.
    accessor := DatabaseAccessor forLogin: login.
    accessor loginIfError: [:err | Transcript nextPutAll: err].
    (sess := GlorpSession new) system: (DBAdaptor forPlatform: login database).
    sess accessor: accessor.
    ^sess


disconnectFromDatabase: sess
    sess ifNotNil: [ sess accessor logout ]