Xbasic

SQL::Schema Object

Description

SQL::Schema Object properties and methods.

A SQL::Schema object (a database description) is a container for one or more SQL::TableInfo objects (table descriptions).

Discussion

This example creates an array containing five SQL::TableInfo objects.

As of the writing of this help topic, it is impossible to DIM an array of objects based on a class. The following code sample shows a work-around.

dim ti as SQL::TableInfo
dim arr[5] as P
arr[1] = ti
for i = 2 to 5
    arr[i] = ti.clone()
next i

The TableInDependencyOrder property lists all tables in the order they should be created and populated in copying them to a new database.

Example

This example interactive window session shows how to use the sql::schema object and the tablesReferencing and tablesReferencedBy methods of the sql::schema object. The connection string is pointing to a SQL Server version of Northwind.

dim cn as sql::connection 
 ?cn.open("::Name::nw")
 = .T.
 dim s as sql::Schema
 ?cn.GetSchema(s)
 = .T.

 ?s.TableNumber("customers")
 = 2
 dim tiCustomer as sql::TableInfo
 tiCustomers = s.table[2]
 r1 = s.TablesReferencedBy(tiCustomers)
 ?r1.table.count 
 = 0
 r2 = s.TablesReferencing(tiCustomers)
 ?r2.table.Count
 = 1
 ?r2.table1.name 
 = "Orders"
 dim tiOrders as sql::TableInfo 
 ?s.tableNumber("orders")
 = 5
 tiOrders = s.table[5]
 r3 = s.TablesReferencedBy(tiOrders)
 ?r3.Table.count 
 = 3
 ?r3.table[1].name 
 = "Customers"
 ?r3.table[2].name 
 = "Employees"
 ?r3.table[3].name 
 = "Shippers"
 r4 = s.TablesReferencing(tiOrders)
 ?r4.Table.count 
 = 1

 ?r4.table[1].name 
 = "Order Details"

Properties

XMLCharacter: The schema in XML format.
NameCharacter: The unique name of the table. Note: The table must be unique for the owner, but may not be globally unique.
NativeAPICharacter: The name of the API active when this object was created.
NativeSyntaxCharacter: The name of the syntax at the time the object was created.
CommentCharacter: The comment stored for the table (if the database supports it).
OwnerCharacter: The SQL database user or group that owns the table.
CatalogCharacter: String Catalog property
SchemaCharacter: String Schema property
TableSQL::TableInfo[]: An array of table ( SQL::TableInfo ) definitions.
TableInDependencyOrderSQL::TableInfo[]: An array of table ( SQL::TableInfo ) definitions ordered from the top of the dependency hierarchy.
CallResultSQL::CallResult: CallResult property

Methods

AddTable Method: Add a Table.
Clear Method: The Clear() method clears out the schema as if it had just been created.
Clone Method: The SQL::Schema.Clone() method makes a copy of a SQL::Schema object and its properties.
ListTables Method: The ListTables() method returns a list of tables in the current cache for the current database.
ListTablesWithTypes Method: Return a list of tables for the current database suffixed with (<type>).
TableNumber Method: Get the index of a Table from the name.
TablesReferencedBy Method: Generate a collection of tables referenced by this table.
TablesReferencing Method: Generate a collection of tables that reference this table.
UpdateStatistics Method: Gather statistical information about the actual tables in the schema.