Oracle SQL Developer

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Managing TablesTo include lowercase characters, special characters, or spaces in an object name, youmust enclose the name in quotation marks (" ") when you type it in a Name field inSQL Developer. Example: "My table"The following topics describe how to view, create, and manage the various types ofobjects in your database schemas:■■■■■Managing TablesManaging IndexesManaging ViewsManaging SequencesManaging Synonyms4.2 Managing TablesTables are the basic unit of data storage in an Oracle database. They hold alluser-accessible data. A table is two-dimensional object comprised of columns androws. For example the employees table includes (vertical) columns called first_name, last_name, and employee_id. Each (horizontal) row in the table contains avalue for employee name and Id number. The most common type of table in an Oracledatabase is a relational table.This topic contains the following topics:■ Column Data Types■ Column Default Values■ Ensuring Data Integrity With Constraints■ Column Constraints■ Table-Level ConstraintsSee Also:■■■Oracle Database Administrator's Guide for information on managingtables.Oracle Database Concepts for conceptual information on tablestypes.Oracle Database SQL Reference for the syntax required to create andalter tables.4.2.1 Column Data TypesData types are required elements that define the nature of the data to be stored in thecolumns of a table. Data types might include a value to indicate the longest value thatcan be placed in the column. When you create a table, you must specify a data type foreach of its columns. For a discussion of data types, see Data Types: Usage Information.These data types define the domain of values that each column can contain or eachargument can have. For example, DATE columns cannot accept the value February29 (except for a leap year) or the values 2 or SHOE. Each value subsequently placed ina column assumes the column data type. For example, if you insert 17-JAN-2004 intoa date column, then Oracle treats the 17-JAN-2004 character string as a date valueafter verifying that it translates to a valid date.4-2 SQL Developer Online Help
Managing TablesIn most cases, you should only need columns of NUMBER, VARCHAR2, and DATE datatypes when creating a definition of a table.When defining numeric data, you can use the precision option to set the maximumnumber of digits in the number, and the scale option to define how many of the digitsare to the right of the decimal point. For example, a field to hold monetary valuesmight be defined as NUMBER(12,2), providing ten digits for the primary unit ofcurrency (dollars, pounds, marks, and so on) and two digits for the secondary unit(cents, pennies, pfennigs, and so on).To define a VARCHAR2 field for character data, you must include the size value. Set thesize to the maximum number of bytes (or, optionally, characters) to be stored in thecolumn. A column to hold postal codes for different countries, for example, might berestricted to 12 bytes by defining it as VARCHAR2(12).DATE columns are automatically formatted by Oracle to include a date and timecomponent. Although both the date and time are stored in a date column, by default,the date portion is automatically displayed for you, when retrieving date data.However, Oracle Database enables you great flexibility in how you can display yourdates and times.4.2.2 Column Default ValuesSee Also: Oracle Database SQL Reference for a complete list ofOracle’s built-in data types.Default values are values that are automatically stored into the column whenever anew row is inserted without a value being provided for the column. When you definea column with a default value, any new rows inserted into the table store the defaultvalue unless the row contains an alternate value for the column. Assign default valuesto columns that contain a typical value. For example, in the departments table, ifmost departments are located at one site, then the default value for the location_idcolumn can be set to this value, such as 1700.Default values can help avoid errors where there is a number, such as zero, thatapplies to a column that has no entry. For example, a default value of zero can simplifytesting, by changing a test like this:IF salary >= 0 AND salary < 50000to the simpler form:IF salary < 50000Depending upon your business rules, you might use default values to represent zeroor FALSE, or leave the default values as NULL to signify an unknown value.Default values can be defined using any literal, or almost any expression includingSYSDATE, which is a SQL function that returns the current date.4.2.3 Ensuring Data Integrity With ConstraintsYou can define integrity constraints to enforce business rules on data in your tables.Business rules specify conditions and relationships that must always be true, or mustalways be false.When an integrity constraint applies to a table, all data in the table must conform tothe corresponding rule. When you issue a SQL statement that inserts or modifies datain the table, Oracle Database ensures that the new data satisfies the integrityconstraint, without the need to do any checking within your program.Database Objects: Usage Information 4-3
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Oracle SQL DeveloperOnline HelpRele
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Contents1 SQL Developer Concepts an
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3.12 Create/Edit Index ............
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6.3.2 Updating Data With the UPDATE
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10.2.5 SQL*Plus SET Commands.......
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SQL Developer User InterfaceThe men
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SQL Developer User InterfaceThe Com
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Database Objects1.2 Database Object
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Database Objectscontaining the mast
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Database Objects■■■■■■
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Database ConnectionsWhen you start
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Running and Debugging Functions and
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Using the SQL WorksheetRelated Topi
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Using the SQL WorksheetScript Runne
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Using the SQL Worksheetmentioned in
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Reports1.9 ReportsRelated TopicsRun
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Reports1.9.3 Table reportsTable rep
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Reportsissues and vulnerabilities,
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SQL Developer Preferencesand the SQ
Page 40 and 41: SQL Developer Preferences1.10.3 Cod
Page 42 and 43: SQL Developer PreferencesSQL Develo
Page 44 and 45: SQL Developer User Information: Loc
Page 46 and 47: Supplementary Oracle Database Infor
Page 48 and 49: Creating a Table (Books)the table t
Page 50 and 51: Creating a Table (Transactions)Colu
Page 52 and 53: Creating a SequenceName: for_key_bo
Page 54 and 55: Creating a PL/SQL Procedure2.6 Crea
Page 56 and 57: Using the SQL Worksheet for Queries
Page 58 and 59: Script for Creating and Using the L
Page 60 and 61: Script for Creating and Using the L
Page 62 and 63: Check for UpdatesTo remove the effe
Page 64 and 65: Select Library3.8 Select LibraryThi
Page 66 and 67: Create PL/SQL Function, Procedure,
Page 68 and 69: Create Table (quick creation)Relate
Page 70 and 71: Create/Edit Table (with advanced op
Page 78 and 79: Create Type (User-Defined)For more
Page 80 and 81: Create/Edit ViewTest Syntax: Checks
Page 82 and 83: Configure File Type AssociationsDia
Page 84 and 85: Find/Replace TextTo add a type of o
Page 86 and 87: Save/Save As3.37 Save/Save As3.38 S
Page 88 and 89: SQL*Plus Location3-28 SQL Developer
Page 92 and 93: Managing Tables4.2.4 Column Constra
Page 94 and 95: Managing Indexes4.3 Managing Indexe
Page 96 and 97: Managing Indexesuseful when all of
Page 98 and 99: Managing Views4.4 Managing Views4.3
Page 100 and 101: Managing Synonyms4-12 SQL Developer
Page 102 and 103: Storing Numeric Data■■NCHAR and
Page 104 and 105: Storing Numeric DataThe absence of
Page 106 and 107: Storing Datetime Data5.4.1.2 Using
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Page 110 and 111: Retrieving Data With Queries■■
Page 112 and 113: Retrieving Data With QueriesSee Als
Page 114 and 115: Retrieving Data With QueriesSee Als
Page 116 and 117: Transaction Control Statements6.3.2
Page 118 and 119: Using Pseudocolumns, Sequences, and
Page 124 and 125: Using SQL Data Definition Language
Page 126 and 127: Using SQL Data Definition Language
Page 128 and 129: Entering and Executing PL/SQL CodeY
Page 130 and 131: Utilizing the Main Features of PL/S
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Utilizing the Main Features of PL/S
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Handling PL/SQL ErrorsTo handle une
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Handling PL/SQL ErrorsIf you redecl
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Handling PL/SQL Errors7-26 SQL Deve
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Overview of Packages and Subprogram
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Managing Packagescalling procedures
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Oracle Product-Specific PackagesTab
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Oracle Product-Specific PackagesTab
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Oracle Product-Specific Packages8-1
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Overview of Triggers9.1.1 Types of
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Overview of Triggers■■A trigger
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Designing TriggersNote: A procedure
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Using SQL*Plus■■■Running Scri
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Using SQL*PlusA SQL script file is
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Using SQL*Plus10-6 SQL Developer On
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Overview of Globalization Support
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Setting up the Globalization Suppor
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SQL and PL/SQL Programming with Uni
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SQL and PL/SQL Programming with Uni
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Locale-Dependent SQL Functions with
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Locale-Dependent SQL Functions with
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COLLECTION_IS_NULL exception, 7-22c
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overview, 7-14EXPLAIN PLANexecution
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NLSSORT SQL function, 11-21NO_DATA_
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displaying output from PL/SQL, 7-9s
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disabling, 9-4enabling, 9-4error co
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