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How To Use Existing Values in UPDATE Statements
How To Use Existing Values in UPDATE Statements? - Oracle DBA FAQ - Understanding SQL DML Statements If a row matches the WHERE clause in a UPDATE statement, existing values in this row can be used in expressions to provide new values in the SET clause. Existing values are represented by columns in ...
2007-04-21, 5142👍, 0💬

What Is a Initialization Parameter File
What Is a Initialization Parameter File? - Oracle DBA FAQ - Oracle Basic Concepts An initialization parameter file is a text file that contains a list of initialization parameters. The file should be written in the client's default character set. Sample initialization parameter files are provided on...
2007-04-21, 4971👍, 0💬

What is System Global Area (SGA)
What is System Global Area (SGA)? - Oracle DBA FAQ - Oracle Basic Concepts The System Global Area (SGA) is a memory area that contains data shared between all database users such as buffer cache and a shared pool of SQL statements. The SGA is allocated in memory when an Oracle database instance is s...
2007-04-21, 5252👍, 0💬

How To Delete an Existing Row from a Table
How To Delete an Existing Row from a Table? - Oracle DBA FAQ - Understanding SQL DML Statements If you want to delete an existing row from a table, you can use the DELETE statement with a WHERE clause to identify that row. Here is good sample of DELETE statements: INSERT INTO fyi_links (url, id) VAL...
2007-04-21, 5219👍, 0💬

What Happens If the UPDATE Subquery Returns Multiple Rows
What Happens If the UPDATE Subquery Returns Multiple Rows? - Oracle DBA FAQ - Understanding SQL DML Statements If a subquery is used in a UPDATE statement, it must return exactly one row for each row in the update table that matches the WHERE clause. If it returns multiple rows, Oracle server will g...
2007-04-21, 7181👍, 0💬

What Is a Server Parameter File
What Is a Server Parameter File? - Oracle DBA FAQ - Oracle Basic Concepts A server parameter file is a binary file that acts as a repository for initialization parameters. The server parameter file can reside on the machine where the Oracle database server executes. Initialization parameters stored ...
2007-04-21, 4873👍, 0💬

What Is a Parameter File
What Is a Parameter File? - Oracle DBA FAQ - Oracle Basic Concepts A parameter file is a file that contains a list of initialization parameters and a value for each parameter. You specify initialization parameters in a parameter file that reflect your particular installation. Oracle supports the fol...
2007-04-21, 5124👍, 0💬

How To Use "OUT" Parameter Properly
How To Use "OUT" Parameter Properly? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions Here are the rules about OUT parameters: A formal OUT parameter acts like an un-initialized variable. It must be assigned with new values before the end of the procedure or function. An actual O...
2007-04-21, 5294👍, 0💬

How To Use "IN OUT" Parameter Properly
How To Use "IN OUT" Parameter Properly? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions Here are the rules about IN OUT parameters: A formal IN OUT parameter acts like an initialized variable. An actual IN OUT parameter must be a variable. An actual IN OUT parameter passes a cop...
2007-04-21, 7066👍, 0💬

How To Define Default Values for Formal Parameters
How To Define Default Values for Formal Parameters? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions If you have an IN parameter, you can make it as an optional parameter for the calling statement by defining the formal parameter with the DEFAULT clause. This gives you the freedo...
2007-04-21, 5504👍, 0💬

What Are Named Parameters
What Are Named Parameters? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions Named parameters are actual parameters specified not by position but by providing formal parameter names when calling the procedure or function. The main advantage of named parameters is that the caller d...
2007-04-21, 7144👍, 0💬

What Is the Scope of a Local Variable
What Is the Scope of a Local Variable? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions The scope of a variable can be described with these rules: A variable is valid within the procedure or function where it is defined. A variable is also valid inside a sub procedure or function...
2007-04-21, 5824👍, 0💬

How To Delete Multiple Rows from a Table
How To Delete Multiple Rows from a Table? - Oracle DBA FAQ - Understanding SQL DML Statements You can delete multiple rows from a table in the same way as deleting a single row, except that the WHERE clause will match multiple rows. The tutorial exercise below deletes 3 rows from the fyi_links table...
2007-04-21, 5582👍, 0💬

How To Delete All Rows a Table
How To Delete All Rows a Table? - Oracle DBA FAQ - Understanding SQL DML Statements If you want to delete all rows from a table, you have two options: Use the DELETE statement with no WHERE clause. Use the TRUNCATE TABLE statement. The TRUNCATE statement is more efficient the DELETE statement. The t...
2007-04-21, 5346👍, 0💬

What Is an Oracle Database
What Is an Oracle Database? - Oracle DBA FAQ - Oracle Basic Concepts An Oracle database is a collection of data treated as a big unit in the database server.
2007-04-21, 4644👍, 0💬

What Is an Oracle Instance
What Is an Oracle Instance? - Oracle DBA FAQ - Oracle Basic Concepts Every running Oracle database is associated with an Oracle instance. When a database is started on a database server (regardless of the type of computer), Oracle allocates a memory area called the System Global Area (SGA) and start...
2007-04-21, 4737👍, 0💬

How To Select All Columns of All Rows from a Table
How To Select All Columns of All Rows from a Table? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements The simplest query statement is the one that selects all columns of all rows from a table: "SELECT * FROM table_name;". The (*) in the SELECT clause tells the query to return all columns....
2007-04-21, 6561👍, 0💬

What Is a SELECT Query Statement
What Is a SELECT Query Statement? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements The SELECT statement is also called the query statement. It is the most frequently used SQL statement in any database application. A SELECT statement allows you to retrieve data from one or more tables, or...
2007-04-21, 4900👍, 0💬

What Is Oracle
What Is Oracle? - Oracle DBA FAQ - Oracle Basic Concepts Oracle is a company. Oracle is also a database server, which manages data in a very structured way. It allows users to store and retrieve related data in a multiuser environment so that many users can concurrently access the same data. All thi...
2007-04-21, 5273👍, 0💬

How To Select Some Columns from a Table
How To Select Some Columns from a Table? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you want explicitly tell the query to some columns, you can specify the column names in SELECT clause. The following select statement returns only two columns from the table "departments": SQL> S...
2007-04-21, 5385👍, 0💬

How To Select Some Rows from a Table
How To Select Some Rows from a Table? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you don't want select all rows from a table, you can specify a WHERE clause to tell the query to return only the rows that meets the condition defined in the WHERE clause. The following select state...
2007-04-21, 5147👍, 0💬

Can the Query Output Be Sorted by Multiple Columns
Can the Query Output Be Sorted by Multiple Columns? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements You can specifying multiple columns in the ORDER BY clause as shown in the following example statement, which returns employees' salaries sorted by department and salary value: SQL> SELEC...
2007-04-20, 5269👍, 0💬

How To Sort the Query Output
How To Sort the Query Output? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you want the returning rows to be sorted, you can specify a sorting expression in the ORDER BY clause. The following select statement returns rows sorted by the values in the "manager_id" column: SQL> SELEC...
2007-04-20, 5273👍, 0💬

How To Use SELECT Statement to Count the Number of Rows
How To Use SELECT Statement to Count the Number of Rows? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you want to count the number of rows, you can use the COUNT(*) function in the SELECT clause. The following select statement returns the number of rows in the "department" table: ...
2007-04-20, 7347👍, 0💬

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