The database assembly build tool is a tool to allow a developer to select database schema items (tables, views, stored procedures, users etc.) and export the DDL to create these items to a SQL file. This file can then be run against another database to recreate the source schema. It is intended to be extensible to allow it to be adapted to any database platform, and a SQL server implementation is included in this article code to show this.
DataSchemaBase is the "contract" between the data schema provider and the database build wizard. It sets out a set of interfaces that the data schema provider must implement in order that it can be used to generate the DDL.
IDataSource class is the root of the data schema provider. It gives information about the capabilities of the data schema provider (does it support stored procedures, views etc.) and reads only collections of those database objects.
Public MustInherit Class IDataSourceBase
Public MustOverride ReadOnly Property Indexes() As IIndexCollection
Public MustOverride ReadOnly Property SupportsViews() As Boolean
This defines what information the database wizard needs to know about a table - essentially, the fields that make up the table and the permissions that are applicable to that table.
Public MustOverride ReadOnly Property Fields() As IFieldCollection
Public MustOverride ReadOnly Property Permissions() As IPermissionCollection
In addition, it provides a
DDL which is the SQL statement(s) that would be needed to recreate this table.
Each of the other database item types have a similar implementation class that is broadly like
This DLL contains a SQL Server specific implementation of the
DataSchemaBase classes to allow you to extract the DDL for a SQL Server (or MSDE) database.
This implements the
IDataSource interface for a SQL server database. Since this database platform supports all the database item types listed, it returns true for the
SupportsStoredProcedures and related properties, and has to provide an implementation of the
Storedprocedures and related object collections.
This type safe collection returns a list of all the tables in the selected database. It does this by querying the table sysobjects:
Public Class SQLServerTables
Public Sub New(ByVal dbConn As OleDb.OleDbConnection)
Const SQL_GETTABLES = "select name from sysobjects where type = 'U'"
This class returns the DDL required to create the specific table. It does this with a hard coded part (
create table), and then iterates through the fields and permissions appending the DDL for them.
There are similar classes implementing each of the other database object types (view, stored procedure etc.)
This is a single form Windows application that uses the WizardControl from Divil to allow the developer to select and connect to a database, then select the objects to be extracted and lastly the target file name, then produce the DDL.
Plug-in data schema providers
The different types of data schema providers are read in from the application configuration file to allow you to add more providers without having to recompile the application.
<dataSchemaProvidor Key="SQL Server"
Step 1: Connecting to the database
The first page in the wizard presents you with a textbox into which you put the ODBC connection string, and a drop down box to select the data schema provider. Once these are both filled in, it goes off and gets all the DB items from the database selected. This may take a minute or two on a large database schema.
Step 2: Selecting the objects to extract
The second step is to select the tables, views, users, stored procedures, triggers or user groups you want to extract. You need to have at least one object type selected before you can proceed to step 3.
Step 3: Selecting the output
Step 3 is to select a SQL file name to write the DDL to. If the file already exists, you will be prompted whether or not to delete it. You can then use the output file with the OSQL command line to generate the data schema on the target database.