🗊Презентация Writing executable statements

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Writing executable statements, слайд №1Writing executable statements, слайд №2Writing executable statements, слайд №3Writing executable statements, слайд №4Writing executable statements, слайд №5Writing executable statements, слайд №6Writing executable statements, слайд №7Writing executable statements, слайд №8Writing executable statements, слайд №9Writing executable statements, слайд №10Writing executable statements, слайд №11Writing executable statements, слайд №12Writing executable statements, слайд №13Writing executable statements, слайд №14Writing executable statements, слайд №15Writing executable statements, слайд №16Writing executable statements, слайд №17Writing executable statements, слайд №18Writing executable statements, слайд №19Writing executable statements, слайд №20Writing executable statements, слайд №21Writing executable statements, слайд №22Writing executable statements, слайд №23Writing executable statements, слайд №24Writing executable statements, слайд №25Writing executable statements, слайд №26Writing executable statements, слайд №27Writing executable statements, слайд №28Writing executable statements, слайд №29

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Writing Executable Statements
Описание слайда:
Writing Executable Statements

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Objectives
After completing this lesson, you should be able to do the following:
Identify lexical units in a PL/SQL block
Use built-in SQL functions in PL/SQL
Describe when implicit conversions take place and when explicit conversions have to be dealt with
Write nested blocks and qualify variables with labels
Write readable code with appropriate indentation
Use sequences in PL/SQL expressions
Описание слайда:
Objectives After completing this lesson, you should be able to do the following: Identify lexical units in a PL/SQL block Use built-in SQL functions in PL/SQL Describe when implicit conversions take place and when explicit conversions have to be dealt with Write nested blocks and qualify variables with labels Write readable code with appropriate indentation Use sequences in PL/SQL expressions

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Lexical Units in a PL/SQL Block
Lexical units:
Are building blocks of any PL/SQL block
Are sequences of characters including letters, numerals, tabs, spaces, returns, and symbols
Can be classified as:
Identifiers: v_fname, c_percent
Delimiters: ; , +, -
Literals: John, 428, True
Comments: --, /* */
Описание слайда:
Lexical Units in a PL/SQL Block Lexical units: Are building blocks of any PL/SQL block Are sequences of characters including letters, numerals, tabs, spaces, returns, and symbols Can be classified as: Identifiers: v_fname, c_percent Delimiters: ; , +, - Literals: John, 428, True Comments: --, /* */

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PL/SQL Block Syntax and Guidelines
Literals
Character and date literals must be enclosed in single quotation marks.
Numbers can be simple values or in scientific notation.
Statements can span several lines.
Описание слайда:
PL/SQL Block Syntax and Guidelines Literals Character and date literals must be enclosed in single quotation marks. Numbers can be simple values or in scientific notation. Statements can span several lines.

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Commenting Code
Prefix single-line comments with two hyphens (--).
Place multiple-line comments between the symbols /* and */.
Example:
Описание слайда:
Commenting Code Prefix single-line comments with two hyphens (--). Place multiple-line comments between the symbols /* and */. Example:

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SQL Functions in PL/SQL
Available in procedural statements:
Single-row functions
Not available in procedural statements:
DECODE
Group functions
Описание слайда:
SQL Functions in PL/SQL Available in procedural statements: Single-row functions Not available in procedural statements: DECODE Group functions

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SQL Functions in PL/SQL: Examples
Get the length of a string:
Get the number of months an employee has worked:
Описание слайда:
SQL Functions in PL/SQL: Examples Get the length of a string: Get the number of months an employee has worked:

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Using Sequences in PL/SQL Expressions
Starting in 11g:
Before 11g:
Описание слайда:
Using Sequences in PL/SQL Expressions Starting in 11g: Before 11g:

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Data Type Conversion
Converts data to comparable data types
Is of two types:
Implicit conversion
Explicit conversion
Functions:
TO_CHAR
TO_DATE
TO_NUMBER
TO_TIMESTAMP
Описание слайда:
Data Type Conversion Converts data to comparable data types Is of two types: Implicit conversion Explicit conversion Functions: TO_CHAR TO_DATE TO_NUMBER TO_TIMESTAMP

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Описание слайда:

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Data Type Conversion
Описание слайда:
Data Type Conversion

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Nested Blocks
PL/SQL blocks can be nested.
An executable section (BEGIN … END) can contain nested blocks.
An exception section can contain 
nested blocks.
Описание слайда:
Nested Blocks PL/SQL blocks can be nested. An executable section (BEGIN … END) can contain nested blocks. An exception section can contain nested blocks.

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Nested Blocks: Example
Описание слайда:
Nested Blocks: Example

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Variable Scope and Visibility
Описание слайда:
Variable Scope and Visibility

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Описание слайда:

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Qualify an Identifier
Описание слайда:
Qualify an Identifier

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Determining Variable Scope: Example
Описание слайда:
Determining Variable Scope: Example

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Описание слайда:

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Operators in PL/SQL
Logical
Arithmetic
Concatenation 
Parentheses to control order 
of operations
Exponential operator (**)
Описание слайда:
Operators in PL/SQL Logical Arithmetic Concatenation Parentheses to control order of operations Exponential operator (**)

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Operators in PL/SQL: Examples
Increment the counter for a loop.
Set the value of a Boolean flag. 
Validate whether an employee number contains a value.
Описание слайда:
Operators in PL/SQL: Examples Increment the counter for a loop. Set the value of a Boolean flag. Validate whether an employee number contains a value.

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Programming Guidelines
Make code maintenance easier by:
Documenting code with comments
Developing a case convention for the code
Developing naming conventions for identifiers and other objects
Enhancing readability by indenting
Описание слайда:
Programming Guidelines Make code maintenance easier by: Documenting code with comments Developing a case convention for the code Developing naming conventions for identifiers and other objects Enhancing readability by indenting

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Indenting Code
For clarity, indent each level of code.
Описание слайда:
Indenting Code For clarity, indent each level of code.

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Quiz
You can use most SQL single-row functions such as number, character, conversion, and date single-row functions in PL/SQL expressions.
True
False
Описание слайда:
Quiz You can use most SQL single-row functions such as number, character, conversion, and date single-row functions in PL/SQL expressions. True False

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Summary
In this lesson, you should have learned how to: 
Identify lexical units in a PL/SQL block
Use built-in SQL functions in PL/SQL
Write nested blocks to break logically related functionalities
Decide when to perform explicit conversions
Qualify variables in nested blocks
Use sequences in PL/SQL expressions
Описание слайда:
Summary In this lesson, you should have learned how to: Identify lexical units in a PL/SQL block Use built-in SQL functions in PL/SQL Write nested blocks to break logically related functionalities Decide when to perform explicit conversions Qualify variables in nested blocks Use sequences in PL/SQL expressions

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Practice 3: Overview
This practice covers the following topics:
Reviewing scoping and nesting rules
Writing and testing PL/SQL blocks
Описание слайда:
Practice 3: Overview This practice covers the following topics: Reviewing scoping and nesting rules Writing and testing PL/SQL blocks

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Writing executable statements, слайд №28
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Writing executable statements, слайд №29
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