Transcript Advantage Data Dictionary

Advantage Data Dictionary
agenda
• Creating and Managing Data Dictionaries
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Tables, Indexes, Fields, and Triggers
Defining Referential Integrity
Defining Views
Data Dictionary Links
User, User Groups, and Permissions
• Migrating an Existing Applications to Data
Dictionaries
• Upgrading Data Dictionaries
architecture
• Consists of three files
– .ADD – Advantage Data Dictionary file
– .AM - The memo file for the Advantage Data Dictionary
– .AI - The index file for the Advantage Data Dictionary
• Only the .ADD and .AM files should be
distributed to the client site to avoid collation
sequence differences
– The .AI file will be created automatically when the data
dictionary is first opened
data dictionary properties*
• Dictionary Name
• Paths
– Database -- where to create the .ADD, .AM, and .AI files
– Default Path -- where tables are created and opened by default
– Temporary Path -- where temporary SQL files are created
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Logins Required and Check User Rights
Data Dictionary File Encryption
Table Encryption
Description
Advantage Internet Access
Dictionary Version
tables and indexes
• Data dictionaries can contain both ADTs and
DBFs
• Existing tables can be added one at a time or
in groups
• All tables created while connected to a data
dictionary as the system administrator
(ADSSYS) will be automatically added to the
dictionary
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tables and indexes
• ADT tables bound to a data dictionary cannot
be opened as free table
• DBF tables can still be opened as free tables
• All indexes get opened automatically when
the table is opened
• Indexes created by a non-Administrative
user are temporary and deleted when the
users disconnects
ADT table features
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Referential Integrity
Default Field Values
Record and Field Level Constraints
More Secure Encryption
table properties*
• Auto Create
• Description
• Permission Level
– Level 1: reading field without rights returns NULL, filtering
allowed, equivalent to Paradox behavior
– Level 2: reading field without rights returns NULL, filtering
returns error, default Advantage permission level
– Level 3: can only access via SQL, reading field without rights
returns error, equivalent to MS SQL Server behavior
• Encryption
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table properties
• Record Level Constraint
– Failed Validation Message
– Validates changes for an entire record
– Performed when a record insert or update is written/flushed to
the Advantage server
– Can be any valid Advantage Expression Engine expression
index properties
• Default Index
– Works in conjunction with the TDataSet Descendant and the
OLE DB Provider
• Primary Index
– Advantage Index files only (ADIs)
– Can be used as primary key in a Referential Integrity
relationship
• Index Page Size
– Advantage Index files only (ADIs)
– Larger page sizes can improve performance when dealing with
large numbers of records
field properties*
• Field Level Constraints
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Minimum Field Value
Maximum Field Value
Value Required (are NULL values allowed)
Failed Validation Message
• Default Field Value
– Any valid Advantage Expression Engine expression
• Field Description
triggers
new
• Code automatically executed by the server on
INSERT, UPDATE, and DELETE operations
• 5 types of triggers
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SQL Scripts
Standard 32-bit Windows DLLs
Windows COM DLLs
Linux Shared Objects
.NET Assemblies
• Excellent for enforcing business rules and creating
audit trails
referential integrity
• Referential Integrity (RI) is the means by
which primary/foreign key relationships are
enforced in a database
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Ensures that a database is logically consistent
Primary Table and Primary Key
Foreign Table and Foreign Key
Update and Delete Rules
Primary Key Violation Error Message
Cascade Error Message
referential integrity rules*
• RI Deletion Rules are enforced when the
primary key is deleted from the parent table
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RESTRICT
CASCADE
SET NULL
SET DEFAULT
• RI Update Rules are enforced when the
primary key is modified in the parent table
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RESTRICT
CASCADE
SET NULL
SET DEFAULT
views
• Views are virtual tables that are the result of
an SQL statement
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Virtual table
Contains data from multiple tables or views
Created by the data dictionary administrator
Excellent for complex queries
Is updateable if the underlying SQL cursor is updateable
advantage extended procedures
• Executed by the Advantage Database Server
• Decreases network traffic
• Supports any programming language that
can create a:
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Standard 32-bit Windows DLL
Windows COM DLL
Linux Shared Object
.NET Assembly
• Excellent for shared business rules
data dictionary links
• Data dictionary links provide access to tables in
other data dictionaries
• SELECT statements only
• Tables are read-only
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data dictionary links
• Two types of links
• Direct path links
– SELECT * FROM employees a, “\\server\share\hr.add”.employees b
WHERE a.employee_id = b.employee_id
– Authentication to linked dictionary is done using same User ID and
Password as the current dictionary
• Alias links using dot notation
– UPDATE customers SET address = (SELECT address FROM
backup.customers b WHERE b.cust_id = customers.cust_id )
– Authentication to linked dictionary can be done with same User ID and
Password or via User Name & Password specified when creating the
Alias
user access permissions
• Control access to database resources
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Tables
Fields
Views
Stored Procedures
Data Dictionary Links
• Groups and Users
• Set these database properties before they
take effect
– Logins Required
– Check User Rights
managing permissions*
• Permissions are cumulative
• Permissions granted on a field(s) imply those
same permissions on the table for that
field(s)
• Methods to make managing users easier:
– Generic users: Set up one user name shared by several people,
such that each person who uses that user name has the same
rights
– Named users (via group): Set a different user name for each
person, then set up a group that each user name would be a
member of, such that each person has the same rights
managing data dictionaries
new
• Advantage Data Architect (ARC) using the
integrated Advantage Database Manager
• TAdsDictionary component in Advantage
TDataSet Descendant client
• Advantage Client Engine AdsDD* APIs
• System Tables and Procedures
system tables*
• Provide read-only access to dictionary object
properties
• Accessible through SQL
– Located in the system catalog
– Requires the use of dot notation
• Table structures will change as new
properties are added
• Contents of tables varies depending on the
user accessing them
system procedures*
• Allows modification of all dictionary
properties through SQL
• Most properties require Administrative
Access to modify a property
• Available on all Operating Systems
migrating existing applications
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Create the Data Dictionary
Add or Create Tables
Define Referential Integrity Rules
Create Views
Add Advantage Extended Procedures
Add Data Dictionary Links
Create Users and Groups
Set Permissions
data dictionary deployment
• AdsDDDeployDatabase
• Deploy dictionaries to existing sites
• Adds all of your tables, constraints, RI rules,
etc.
upgrading data dictionaries
• Performed using SQL scripts containing:
– SQL data definitions statements
– system procedures
• SQL scripts are generated using the
Dictionary Differentiator in Advantage Data
Architect
• Generating scripts requires two versions of
the data dictionary
Dictionary Differentiator*
• Provides graphical view of the difference
between two dictionaries
• Generates SQL upgrade scripts for an entire
dictionary or a just single object
summary
• Advantage Data Dictionaries provide a
wealth of features unavailable to free tables
• Advantage Data Architect is a useful tool to
create, manage, and upgrade Advantage
Data Dictionaries
Advantage Database Server: The Official Guide (ISBN 0-07223084-3) is a new book, written by Cary Jensen and Loy
Anderson and published by McGraw-Hill/Osborne Media
Group, that systematically guides a developer through key
functionality of Advantage and includes a Companion CD with
code samples and a single-user license of Advantage
Database Server version 7.0.
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