Cost based oracle fundamentals pdf

Book by Pierre Labbe. Book by Fabrice Lemainque. EPUb by Pirmin Lemberger. Building Scalable Apps with Redis and Node. CMMI 1. Gimp 2. Internationalization and Localization Using Microsoft. Learning Stencyl 3. However, you I n can set it to something more relevant to you. To do so, select Preferences from the Tools menu. In the Preferences dialog box, expand the Database node. For example, if you l attempt to perform division by zero, you get an error. However, if you divide a number by null, c the result is a null or unknown.

This heading may not be descriptive and, therefore, may be c r a difficult to understand. You can change a column heading by using a column alias. By O ly default, alias headings appear in uppercase. The result of c r a the query is the same whether the AS keyword is used or not. Also, note that the SQL statement has the column aliases, name and comm, in lowercase, whereas the result of the O ly query displays the column headings in uppercase.

As mentioned in the preceding slide, column headings appear in uppercase by default. Note that the column heading in the output is exactly the same as the column alias.

Columns on either side of the c r a operator are combined to make a single output column. O ly Note that the last name of the employee and the job code are combined to make a single output column. I n Note: You can also concatenate date expressions with other expressions or columns. It is not a l column name or a column alias. It is printed for each row returned. The column l has the heading Employee Details. The spaces improve the readability of the output.

If the literal itself l contains a single quotation mark, you can use the quote q operator and select your own c quotation mark delimiter. By using the q operator, however, brackets [ ] a e are used as the quotation mark delimiters. The string between the brackets delimiters is n t e r U s interpreted as a literal character string. Note that the department numbers are repeated. In the second example in the slide, the numbers in the table.

The command A l displays the column names and the data types, and it shows you whether a column must c r a contain data that is, whether the column has a NOT NULL constraint. In the syntax, table name is the name of any existing table, view, or synonym that is accessible to the user.

It is abbreviated as DESC. Type displays the data type for a column. If c In the syntax: r a the condition is true, the row meeting the condition is returned. Number constants, however, need not be enclosed with single quotation marks.

The range A l that you specify contains a lower limit and an upper limit. However, you must specify the lower limit first. The condition defined l using the IN operator is also known as the membership condition. The IN operator can be used with any data type.

Therefore, using the IN operator has no performance benefits and is used only for logical simplicity. The character pattern—matching operation is c Symbol Description r a referred to as a wildcard search.

Two symbols can be used to construct the search string. This option specifies what the escape character is. This causes the Oracle server to interpret the underscore literally. A null value means that the value is unavailable, r a unassigned, unknown, or inapplicable. The example in the slide retrieves the last names O ly and managers of all employees who do not have a manager. A row is returned only if c r a the overall result of the condition is true.

Further, character strings must be enclosed with quotation marks. The table in the slide lists the default order of precedence. However, you can c calculate first. The example in the slide sorts the result by the most recently hired employee. The slide example sorts the data by annual salary. You can sort query results by more than one column. If you want to reverse the order of a column, specify a e DESC after its name. I want to query different values. You can edit the WHERE clause to provide a different value each time you run the command, but there is also an easier way.

You can create reports that prompt users to supply their own values to restrict the range of a e data returned, by using substitution variables. You can embed substitution variables in a n t e r s command file or in a single SQL statement. A variable can be thought of as a container in which values are temporarily stored. When the statement is run, the stored value is U substituted. If used in scripts that are deployed to users, substitution variables can be subverted for SQL injection attacks.

Use an ampersand c value of each variable. When the statement is executed, SQL Developer prompts the user for an employee I n number and then displays the employee number, last name, salary, and department number c l e for that employee. With the single ampersand, the user is prompted every time the command is executed if the a variable does not exist. The slide shows a query to retrieve the employee names, department numbers, and annual O ly salaries of all employees based on the job title value of the SQL Developer substitution variable.

For each click OK to proceed. The user sees the prompt for the value only c r a once. If you run the query again, you will not be prompted for the value of the variable. At run time, this displays the employee number, name, salary, and c department number for that employee. SQL Developer displays the text of a command after it O ly replaces substitution variables with values, in the Script Output tab as shown in the slide.

You should also have learned how to implement various operators c and conditions. This O ly enables the queries to prompt for the filter condition for the rows during run time. You make the SQL statements more reusable and generic by including c the ampersand substitution.

This is the first of two lessons that explore functions. It focuses on single-row c character, number, and date functions. They accept one or more arguments l and return one value for each row that is returned by the query.

This can be represented by a column name or expression. If n is omitted, all characters to the O end of the string are returned. Note: The functions discussed in this lesson are only some of the available functions. LPAD column expression, n, Returns an expression left-padded to length of n 'string' characters with a character expression.

RPAD column expression, n, Returns an expression right-padded to length of n 'string' characters with a character expression. This is a feature that is available in Oracle8i and later versions. Because both names are now lowercase, a match is found and one n same result: t e r row is selected.

This section describes some of the numeric functions. TRUNC column expression, n n a e Truncates the column, expression, or value to n decimal MOD m,n t e r U s places or, if n is omitted, n defaults to zero Returns the remainder of m divided by n I n Note: This list contains only some of the available numeric functions. If the A l second argument is 0 or is missing, the value is rounded to zero decimal places.

If the second c r a argument is 2, the value is rounded to two decimal places. Conversely, if the second argument is —2, the value is rounded to two decimal places to the left rounded to the nearest unit of O ly lesson.

The DUAL table is useful when you want to I n return a value only once for example, the value of a constant, pseudocolumn, or expression that is not derived from a table with user data. If the r a second argument is 0 or is missing, the value is truncated to zero decimal places. If the second argument is 2, the value is truncated to two decimal places. Conversely, if the second O ly argument is —2, the value is truncated to two decimal places to the left. Valid Oracle dates are between January 1, B.

However, dates are not stored in the database in this format. All the components of the date and time are stored. The complete data might be June 17, , PM.

Use the RR date format element instead of YY so that the century of the return value c r a varies according to the specified two-digit year and the last two digits of the current year. The table in the slide summarizes the behavior of the RR element. As we approach the middle of c a the century, then the RR behavior is probably not what you want. However, when the date column is displayed on the screen, the century component is not displayed by default.

The DATE data type uses 2 bytes for the year information, one for century and one for year. The century value is always included, whether or not it is specified or displayed. For example, you can display c public table called DUAL. Therefore, if you are in a place in Australia and connected to a remote database in a location in the United States U. You can add and subtract number c constants as well as dates. It subtracts the date on which the employee was hired from the c worker has been employed.

Your results may when you run the SQL query. The result can be positive or negative. If date1 is later than date2, the O ly result is positive; if date1 is earlier than date2, the result is negative. The noninteger part of the result represents a portion of the month. The value of n must be an integer and can be negative. If the format model fmt is omitted, date is rounded to the nearest day. If the format model fmt is omitted, date is truncated to the nearest day. When used with A l dates, these functions round or truncate to the specified format model.

Therefore, you can c r a round dates to the nearest year or month. If the format model is month, dates result in the first day of the current month. Dates result in the first day of the next month. If the O ly format model is year, months result in January 1 of the current year. Months result in January 1 of the next year. Manipulate data items b. Accept arguments and return one value per argument c.

Act on each row that is returned d. Return one result per set of rows e. May not modify the data type f. Can be nested g. In some cases, the Oracle server receives data of one data type where it expects data of a O ly different data type. When this happens, the Oracle server can automatically convert the data l server or explicitly by the user. This data type conversion can be done implicitly by the Oracle a e Implicit data type conversions work according to the rules explained in the following slides.

Conversion functions convert a value from one data type to another. Generally, the form of the function I n names follows the convention data type TO data type. The first data type is the input data type and the second data type is the output. Kent Crawford. CMMI 1. Code Generation in Microsoft.

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