Download Basic Database

Database Overview
BasicTerminology
Concepts
SQL syntax
Analysis Terms
Term/Concept
Definition
Relational Model
Represent information with tables or relations
Relation Instance
Table representing entity set or relation; each row
of table representing an entity set represents an
entity.
Relation Schema
Column headings or attribute names
Database Schema Collection of relation schemas
Type Constraint
Values in a column are drawn from that datatype
Data Atomiciy
Single values in a column
Analysis Terms
Term/Concept
Definition or Example
Key
A set of attributes which uniquely identifies an
entity (row) of a relation (table)
Key Constraint
Any relation or table has at most one row for some
combination of values of key attributes
Foreign Key
An attribute of a relation which serves as a primary
key of another relation
Foreign Key
Constraint
There is a tuple or row of the primary key table with
same value as value of foreign key (referential
integrity
SQL
Term/Concept
Definition or Example
Select
Select <Attribute-List> From
<Table-Expression> Where <Condition>
<Attribute-List>
* refers to all attributes or columns
<Table-Expression>
RentalProperty is table
<Condition>
Embedded SQL
in as value of string
variable in front end
ID = PropertyID
sql = "Select * from RentalProperty Where ID=" & Id
ds = ExecuteSql(sql)
RentalProperty Listbox
Selecting a property from Listbox selects
ID of property as SelectedValue property of
Listbox which is used to select property
object.
SQL
Term/Concept
Definition or Example
Example of
returning all
rental properties
for Listbox
sql = "Select * from RentalProperty order by name asc"
Example uses an
order by clause
Gridview for Displaying all payments
SQL
Example of returning all payments (transactions) for Gridview
Public Function FindAllTransactionsByTenant(ByVal TID As Long) As List(Of Transaction)
Dim sql As String
Dim ds As DataSet, dr As DataRow
sql = "Select * from RentalTransaction where TenantID = " & TID & "
Order By Transactiondate Desc"
ds = ExecuteSql(sql)
Dim transactions As New List(Of Transaction)
For Each dr In ds.Tables(0).Rows
Dim c As New Transaction(dr)
transactions.Add(c)
Next
Return transactions
End Function
SQL
Term/Concept
Definition or Example
Insert
New Row
Insert Into Table ( <Attribute_List> ) Values ( <Value_List>)
Example of
inserting a recipe
2 is the
PropertyTypeID for
Apartments
Dim sql As String = "Insert Into
Recipe(Name,Ingredients,Instructions) Values('" &
c.Name & "','" & c.Ingredients & "','" &
c.Instructions & "')"
ExecuteSql(sql)
SQL
Term/Concept
Definition or Example
Insert
New Row
Insert Into Table ( <Attribute_List> ) Values ( <Value_List>)
Example of
inserting a recipe
2 is the
PropertyTypeID for
Apartments
Dim sql As String = "Insert Into
Recipe(Name,Ingredients,Instructions) Values('" &
c.Name & "','" & c.Ingredients & "','" &
c.Instructions & "')"
ExecuteSql(sql)
SQL
Term/Concept
Definition or Example
Insert
New Row
Insert Into Table ( <Attribute_List> ) Values ( <Value_List>)
Example of
inserting a recipe
Dim sql As String = "Insert Into
Recipe(Name,Ingredients,Instructions) Values('" &
c.Name & "','" & c.Ingredients & "','" &
c.Instructions & "')"
ExecuteSql(sql)
SQL
Term/Concept
Definition or Example
Update
Existing Row
Update Table Set ( <Attribute_Value_List>)
Example of
updating a recipe
Public Sub UpdateRecipe(ByVal c As Recipe)
Dim sql As String = "Update Recipe Set " & _
"Name ='" & c.Name & "'," & _
c.ID is the ID of the
"Ingredients ='" & c.Ingredients & "'," & _
recipe to be updated
"Instructions = '" & c.Instructions & "' Where
ID=" & c.ID
ExecuteSql(sql)
End Sub