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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, 5285👍, 0💬

How To Loop through Data Rows in the Implicit Curosr
How To Loop through Data Rows in the Implicit Curosr? - Oracle DBA FAQ - Working with Cursors in PL/SQL You use the FOR ... IN ... LOOP statement to loop through data rows in the implicit cursor as the following syntax: FOR row IN dml_statement LOOP (statement block with row.field) END LOOP; Here "r...
2007-04-29, 5284👍, 0💬

How Does Oracle Handle Read Consistency
How Does Oracle Handle Read Consistency? - Oracle DBA FAQ - Understanding SQL Transaction Management Oracle supports two options for you on how to maintain read consistency: READ WRITE (the default option), also called statement-level read consistency. READ ONLY, also called transaction-level read c...
2007-04-18, 5282👍, 0💬

How To Execute a Stored Program Unit
How To Execute a Stored Program Unit? - Oracle DBA FAQ - Introduction to PL/SQL If you want to execute a stored program unit, you can use the EXECUTE statement. The example script below shows how to executes a stored program unit: SQL> set serveroutput on; SQL> CREATE PROCEDURE Hello AS 2 BEGIN 3 DB...
2007-04-25, 5280👍, 0💬

What Privilege Is Needed for a User to Connect to Oracle Server
What Privilege Is Needed for a User to Connect to Oracle Server? - Oracle DBA FAQ - Managing Oracle User Accounts, Schema and Privileges Oracle deny connection to users who has no CREATE SESSION privilege. Try the following tutorial exercise, you will find out how Oracle denies connection: >.\bin\sq...
2007-05-02, 5278👍, 0💬

How To Connect the Oracle Server as SYSDBA
How To Connect the Oracle Server as SYSDBA? - Oracle DBA FAQ - Creating New Database Instance Manually This is Step 4. The best way to connect to the Oracle server as an administrator is to use SQL*Plus. You need to run SQL*Plus with /nolog option and use the CONNECT with blank user name, blank pass...
2007-04-23, 5278👍, 0💬

How To Define a Cursor Variable
How To Define a Cursor Variable? - Oracle DBA FAQ - Working with Cursors in PL/SQL To define cursor variable, you must decide which REF CURSOR data type to use. There are 3 ways to select a REF CURSOR data type: Define your own specific REF CURSOR types using the TYPE ... RETURN statement. Define yo...
2007-04-28, 5277👍, 0💬

How To Pass Parameters to Procedures
How To Pass Parameters to Procedures? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions Store procedures or functions can take parameters. You need to define parameters while defining the procedure, and providing values to parameters while calling the procedure. The script below s...
2007-04-26, 5275👍, 0💬

What Is a Database Table
What Is a Database Table? - Oracle DBA FAQ - Managing Oracle Database Tables A database table is a basic unit of data logical storage in an Oracle database. Data is stored in rows and columns. You define a table with a table name, such as employees, and a set of columns. You give each column a colum...
2007-05-03, 5274👍, 0💬

How To Use Attributes of the Implicit Cursor
How To Use Attributes of the Implicit Cursor? - Oracle DBA FAQ - Working with Cursors in PL/SQL Right after executing a DML statement, you retrieve any attribute of the implicit cursor by using SQL%attribute_name, as shown in the following tutorial exercise: CREATE TABLE student (id NUMBER(5) PRIMAR...
2007-04-29, 5273👍, 0💬

How To Call a Stored Function with Parameters
How To Call a Stored Function with Parameters? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions You can define a function that takes parameters, provide values to those parameters when calling the function. Here is a good example of a function with a parameter: SQL> CREATE OR REP...
2007-04-25, 5273👍, 0💬

What To Do If DBA Lost the SYSTEM Password
What To Do If DBA Lost the SYSTEM Password? - Oracle DBA FAQ - Introduction to Command-Line SQL*Plus Client Tool If the DBA lost the password of the SYSTEM user account, he/she can go to the Oracle server machine, and run SQL*Plus on server locally with the operating system authentication method to ...
2007-04-28, 5270👍, 0💬

What Are the Differences between DATE and TIMESTAMP
What Are the Differences between DATE and TIMESTAMP? - Oracle DBA FAQ - Understanding SQL Basics The main differences between DATE and TIMESTAMP are: DATE stores values as century, year, month, date, hour, minute, and second. TIMESTAMP stores values as year, month, day, hour, minute, second, and fra...
2007-04-24, 5267👍, 0💬

What Is a Cursor
What Is a Cursor? - Oracle DBA FAQ - Working with Cursors in PL/SQL A cursor looks like a variable, but it is not a variable. A cursor looks like a procedure, but it is not a procedure. A cursor is a cursor. It is a logical representation of a resource connects to a set of data rows related to a DML...
2007-04-29, 5263👍, 0💬

How To Write a Query with a Full Outer Join
How To Write a Query with a Full Outer Join? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements If you want to query from two tables with a full outer join, you can use the FULL OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a full outer join from two ...
2007-04-19, 5260👍, 0💬

How To Add a New Column to an Existing Table
How To Add a New Column to an Existing Table? - Oracle DBA FAQ - Understanding SQL DDL Statements If you have an existing table with existing data rows, and want to add a new column to that table, you can use the ALTER TABLE ... ADD statement to do this. Here is an example script: SQL> connect HR/fy...
2007-04-22, 5258👍, 0💬

How Data Locks Are Respected
How Data Locks Are Respected? - Oracle DBA FAQ - Understanding SQL Transaction Management Here are the rules on how data locks are respected: All statements ignore data locks owned its own transaction. SELECT query statements ignores data locks owned by any transactions. INSERT, UPDATE, and DELETE s...
2007-04-17, 5255👍, 0💬

What Is Oracle Server Autotrace
What Is Oracle Server Autotrace? - Oracle DBA FAQ - Introduction to Command-Line SQL*Plus Client Tool Autotrace is Oracle server feature that generates two statement execution reports very useful for performance tuning: Statement execution path - Shows you the execution loop logic of a DML statement...
2007-04-29, 5254👍, 0💬

What Is a Data Lock
What Is a Data Lock? - Oracle DBA FAQ - Understanding SQL Transaction Management A data lock is logical flag the Oracle server is placed on data objects to give an exclusive right to a transaction. Statements in other transactions needs to respect data locks based on certain rules. Rules on data loc...
2007-04-17, 5253👍, 0💬

What Are DML Statements
What Are DML Statements? - Oracle DBA FAQ - Understanding SQL DML Statements DML (Data Manipulation Language) statements are statements to change data values in database tables. The are 3 primary DML statements: INSERT - Inserting new rows into database tables. UPDATE - Updating existing rows in dat...
2007-04-22, 5252👍, 0💬

How To Retrieve Data from an Cursor to a RECORD
How To Retrieve Data from an Cursor to a RECORD? - Oracle DBA FAQ - Working with Cursors in PL/SQL If you have a cursor opened ready to use, you can also use the FETCH statement to retrieve data from the cursor into a RECORD variable as shown in the tutorial exercise below: CREATE OR REPLACE PROCEDU...
2007-04-29, 5251👍, 0💬

How To Assign Data of the Deleted Row to Variables
How To Assign Data of the Deleted Row to Variables? - Oracle DBA FAQ - Working with Database Objects in PL/SQL If a DELETE statement is deleting a single row, you can assign column values of the deleted row to variables by using the RETURNING clause, which an extension of DELETE statements for PL/SQ...
2007-04-27, 5251👍, 0💬

Can Multiple Columns Be Used in GROUP BY
Can Multiple Columns Be Used in GROUP BY? - Oracle DBA FAQ - Understanding SQL SELECT Query Statements You can use multiple columns in the GROUP BY clause as shown in the following example. It returns how many employees are having the same salary in each department: SQL> SELECT department_id, salary...
2007-04-20, 5251👍, 0💬

How To Recover a Dropped Table
How To Recover a Dropped Table? - Oracle DBA FAQ - Managing Oracle Database Tables If you accidentally dropped a table, can you recover it back? The answer is yes, if you have the recycle bin feature turned on. You can use the FLASHBACK TABLE ... TO BEFORE DROP statement to recover a dropped table f...
2007-05-03, 5248👍, 0💬

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