Module 4:Data Objects

Overview

Tables are the main objects that store data

Indexes, views, stored programs and other objects are the support structures

Various table types compared based on data organization

Various index types compared

Native and non-native data type support

Block-level storage architecture

Schema Objects – Table

Tables are the primary objects that store data in rows and columns

Each DBMS offers different types of tables to support different access needs with optimal performance and extended functionality as the goals

Oracle SQL Server

Heap-Organized Table Heap

Clustered Table -

Partitioned Table Partitioned Table

Nested Table XML datatype

Temporary Table Temporary Table

External Table Linked Server

Object Table Table Types

Index-organized Table Clustered Index

Table Types in Oracle and SQL Server

Putting Data in the Table

Heap is the default form of data organization in a table, where data is stored in an unordered manner

Allocation units can extend beyond themselves

Oracle’s index organized tables store data in a B-tree structure in primary key order

Oracle and SQL Server offer local and global temporary tables to store transient application data

Compression is necessary

Demonstration 1: Reviewing Large Allocation Units

In this demonstration you will see how to:

Create a query to view allocation units

Determine why multiple results for a single index might be provided.

SQL Server Table Structures

Clustered Index Structure in SQL Server

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Index Rows ________________________________

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Data Rows ________________________________

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RootIndid = 1Id

Sysindexes

Root node

Intermediate level

Leaf node / data pages

A-Z

W-ZA-D E-H …

…

DebraAndy Charlie

Indexes

Index Structures in Oracle and SQL ServerIndex scheme Oracle SQL Server

B-tree Unique Yes Yes

B-tree Non-unique Yes Yes

B-tree Composite Yes (32 cols) Yes (16 cols)

B-tree Ascending Yes Yes

B-tree Descending Yes Yes

B-tree Cluster Yes Yes

B-tree Reverse key Yes No

B-tree Key compressed Yes No

B-tree Function-based Yes No

B-tree Index organized table Yes Yes (clustered)

B-tree Partitioned Yes No

Bitmap Yes (30 cols) No1

Bitmap Join Yes No1

Constraints

Constraints are data integrity rules defined on columns of a table to enforce certain business rules

Oracle SQL Server

NOT NULL NOT NULL

UNIQUE UNIQUE

PRIMARY KEY PRIMARY KEY

FOREIGN KEY FOREIGN KEY

DEFAULT DEFAULT

CHECK CHECK

Constraints in Oracle and SQL Server

Triggers

Trigger Types Compared

Feature Oracle SQL ServerDML – INSERT Yes YesDML – UPDATE Column/Row RowDML – DELETE Yes YesTiming – BEFORE Yes Yes (INSTEAD OF)Timing – AFTER Yes YesLevel Row/Statement RowViews – INSTEAD OF Yes YesMultiple triggers per action Yes Yes (first/last

specified)DDL Triggers No YesSingle trigger for multiple actions Yes Yes

Views

Both Oracle and SQL Server offer views based on simple queries involving a single table and complex queries based on multiple tablesIndexed views in SQL Server is the only type of view which actually stores dataOracle and SQL Server offer updatable views with INSTEAD OF triggers and WITH CHECK OPTION constraint

View Type Oracle SQL ServerSimple views Yes YesJoin views Yes YesPartitioned views Yes YesUpdatable views Yes YesInline views Yes YesObject views Yes NoIndexed views No Yes

View Types in Oracle and SQL Server

Number Generation and New Names

ORACLE: Sequence ( 0, 1, 2, 3, 4, ……….

• CREATE SEQUENCE SomeNewNumbers • START WITH 0 INCREMENT BY 1

SQL Server: Identity (0, 1, 2, 3, 4, ………..

• CREATE TABLE ASchema.ATable• ( Id int IDENTITY(0,1),• Information nvarchar(12) )

SQL Server: Global Unique Identifiers ( B2794358-DA6A-DD11-829F-001E685F0BC5…

• CREATE TABLE dbo.Globally_Unique_Data• (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL,

• Employee_Name varchar(60)• CONSTRAINT Guid_PK PRIMARY KEY (guid) );

Either: Synonyms

• CREATE SYNONYM MyProduct FOR TheSchema.TheProduct;

Character-Based Data Types

Character-based data types in Oracle and SQL Server

Oracle SQL ServerData Type Size (bytes) Data Type Number of

CharsSize in bytes

Char 1 to 2000 Char 1 to 8000 1 to 8000 fixed

NChar 1 to 2000 (fewer chars) NChar 1 to 4000 2 to 8000 fixed

Varchar 1 to 4000 Varchar Varchar(max)

1 to 80001 to 231-1

0 to 80000 to 2 GB

NVarchar 1 to 4000 (fewer chars) NVarcharNVarchar(max)

1 to 40001 to 230-1

0 to 80000 to 2 GB

Varchar2 1 to 4000

NVarchar2 1 to 4000 (fewer chars)

LONG 1 to 231 Text, Varchar(max)

1 to 231-1 0 to 2 GB

CLOB 1 to 232 Text, Varchar(max)

1 to 231-1 0 to 2 GB

NCLOB 1 to 232 Ntext, Nvarchar(max)

1 to 230-1 0 to 2 GB

Numeric Data Types

Numeric data types in Oracle and SQL ServerOracle SQL Server

Number(19,0) BigInt

Int or Number(10,0) Int

SmallInt or Number(6,0) SmallInt

Number(3,0) TinyInt

Number(p,0) Decimal(p,s)

Number(p,0) Numeric(p,s)

Float or DoublePrecision or Number(38)

Float

Number(1) Bit

Number(19,4) Money

Number(10,4) SmallMoney

Date and Time Types

Oracle SQL ServerData Type Values Data Type Values

Date Date and time to seconds SmallDateTime Date and time to seconds

DateTime Date and time with fractional seconds to 1/300 or 3.33 milliseconds

Calendar 01/01/1753 AD – 01/06/9999 AD (DMY)

Timestamp (TS)Date and time with fractional

seconds (9 digits)

DateTime2 (DT2) Date and time with fractional seconds (7 digits)

Timestamp with time zone (TSTZ) Like TS with zones

Timestamp with local time zone

(TSLTZ)Like TS with relative zones

to users DateTimeOffset Like DT2 with time zone offsets

Calendar – Julian 01/01/4712 BCE - 12/31/4712 CE

Calendar – Gregorian 01/01/0001 AD – 31/12/9999 AD (DMY)

Daylight Savings Time Support Yes Daylight Savings

Time Support No

DATE Date only – Gregorian

TIME Time only with fractional seconds (7 digits)

Binary Data Types

Oracle SQL Server

BLOB Image, Varbinary(max)

Raw Image, Varbinary(max)

Long Raw Image, Varbinary(max)

BFile Similar to Varbinary(max) Filestream

BLOB/Raw(n) Binary(n)

BLOB/Raw(n) Varbinary(n), Varbinary(max)

Binary data types in Oracle and SQL Server

Demonstration 2: Creating a Table

In this demonstration you will see how to:

Create a table taking advantage of filegroups for different types data structures.

Review the results using SSMS

Non-Native Data Types – Beyond Relational

Kim

Raj

Joe Keith

Robert

Jeff

Spatial Hierarchy

Demonstration 3: Beyond Relational

In this demonstration you will see how to:

Define geometric shapes

Define an organizational structure for a company

Oracle and SQL Server Block-Level Data Organization

Microsoft SQLServer Data Page

Row Offsets

OracleData BlockRow Offsets

Page HeaderData Row 1

Data Row 2

Data Row 3

Free Space

Block Header

Free Space

Data Row 3

Data Row 2

Data Row 13 2 1

1 2 3

Review

Reviewed the types of tables found in Oracle and discussed equivalents in SQL Server for heaps, index organized tables and temporary tables

Discussed the supporting schema objects such as indexes and views

Examined the numeric, character and binary data types

Implementation of user-defined data types in Oracle and SQL Server

Comparison of block-level data storage