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Understanding and Managing Indexes in SQL Server
Where to find answers to frequently asked questions on Understanding and Managing Indexes in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Understanding and Managing Indexes in SQL Server. Clear answers are provided with tutorial exe...
2016-11-15, 2585🔥, 0💬

Creating Triggers for INSERT Statements Only in SQL Server
How To Create a Trigger for INSERT Only in SQL Server? The trigger, dml_message, provided in previous tutorials was defined to handle all 3 types of DML statements, INSERT, UPDATE, and DELETE. If you do not want the trigger to handle all 3 types of DML statements, you can list only 1 or 2 of the sta...
2016-10-24, 2585🔥, 0💬

in Oracle
How To Delete All Rows from a Table in Oracle? 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 tutorial exercise shows you a good exa...
2020-01-04, 2584🔥, 0💬

Show Execution Path Reports in Oracle
How To Get Execution Path Reports on Query Statements in Oracle? If your user account has autotrace configured by the DBA, you can use the "SET AUTOTRACE ON EXPLAIN" command to turn on execution path reports on query statements. The tutorial exercise bellow shows you a good example: SQL&gt; CONN...
2020-06-08, 2583🔥, 0💬

Use SQL Statements in PL/SQL in Oracle
How To Use SQL Statements in PL/SQL in Oracle? SQL DML (Data Manipulation Language) statements can be included in PL/SQL code blocks directly without any changes. See the script below for examples: SQL&gt; CREATE TABLE tip (id NUMBER(5) PRIMARY KEY, 2 subject VARCHAR(80) NOT NULL, 3 description ...
2019-03-08, 2581🔥, 0💬

Define an Anonymous Block in Oracle
How To Define an Anonymous Block in Oracle? An anonymous block must have an execution part, which is a group of other PL/SQL statements enclosed in the BEGIN ... END statement. Here is a script on how to define a simple anonymous block with SQL*Plus: SQL&gt; set serveroutput on; SQL&gt; begi...
2018-10-30, 2581🔥, 0💬

Deleting an Existing Row from a Table in MySQL
How To Delete an Existing Row from a Table in MySQL? 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: mysql&gt; INSERT INTO fyi_links (url, id) VALUES ('www.myspace.com', 301);...
2018-01-08, 2581🔥, 0💬

Transaction Waiting for a Data Lock in MySQL
How Long a Transaction Will Wait for a Data Lock in MySQL? If you issue a UPDATE or DELETE statement on a row that has an exclusive lock owned by another session, your statement will be blocked to wait for the other session to release the lock. But the wait will be timed out after the predefined inn...
2017-04-28, 2581🔥, 0💬

What Is a User Account in Oracle
What Is a User Account in Oracle? A user account is identified by a user name and defines the user's attributes, including the following: Password for database authentication Privileges and roles Default tablespace for database objects Default temporary tablespace for query processing work space   ⇒...
2020-07-07, 2580🔥, 0💬

Use DML Statements in PL/SQL in Oracle
Can DML Statements Be Used in PL/SQL in Oracle? Yes, you can run almost any DML statements in PL/SQL directly. To manipulate Oracle database data you can include INSERT, UPDATE, and DELETE statements, directly in PL/SQL programs, without any special notation, as shown in the following sample code: (...
2018-10-13, 2579🔥, 0💬

Example of Passing Parameters to Procedures in Oracle
How To Pass Parameters to Procedures in Oracle? 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 shows you how to do this: SQL&gt; CREATE OR REPLACE PROC...
2019-03-08, 2578🔥, 0💬

Attributes of the Implicit Cursor in Oracle
How To Use Attributes of the Implicit Cursor in Oracle? 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) PRIMARY KEY, first_name VARCHAR(80) NOT NULL, ...
2018-02-01, 2578🔥, 0💬

Execute a Simple Stored Procedure in Oracle
How To Execute a Stored Program Unit in Oracle? 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&gt; set serveroutput on; SQL&gt; CREATE PROCEDURE Hello AS 2 BEGIN 3 DBMS_OUTPUT.PUT_LINE...
2019-03-20, 2577🔥, 0💬

"ALTER FUNCTION" - Modifying Existing Functions in SQL Server
How To Modify an Existing User Defined Function in SQL Server Transact-SQL? If you find a mistake in an existing function previously created, you can drop (delete) it and create it again correctly. But dropping a function may affect other database objects who are depending on this function. So the b...
2016-12-18, 2577🔥, 0💬

Restrictions on External Table Columns in Oracle
What Are the Restrictions on External Table Columns in Oracle? When creating external table columns, you need to watch out some restrictions: "PRIMARY KEY" is not allowed. "NOT NULL" is not allowed. "DEFAULT value" is not allowed.   ⇒ What Is a Directory Object in Oracle ⇐ Load Data through Externa...
2016-11-27, 2576🔥, 0💬

Experiments of Data Locks in Oracle
How To Experiment a Data Lock in Oracle? If you want to have some experience with data locks, you can create two windows running two SQL*Plus sessions. In session 1, you can run a UPDATE statements to create a data lock. Before committing session 2, switch to session 2, and run a UPDATE statements o...
2019-08-08, 2575🔥, 0💬

Scope of Local Variables in Oracle
What Is the Scope of a Local Variable in Oracle? 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 defined. If a variable name is collided with another varia...
2018-10-13, 2575🔥, 0💬

Database Engine Tutorials from SQL Server 2005 Books Online
How to use Transact-SQL statements to access the database engine in SQL Server? Transact-SQL statements can be used to access the database engine directly. Here are some good tutorials provided by the SQL Server 2005 Books Online. See the SQL Server 2005 Tutorials &gt; Database Engine Tutorials ...
2016-11-27, 2575🔥, 0💬

Create a Table for Transaction Testing in MySQL
How To Create a Table for Transaction Testing in MySQL? If you want to learn transaction management, you should create a table with the InnoDB storage engine. The default storage engine MyISAM does not support the transaction concept. The tutorial exercise below shows you a good example of creating ...
2016-10-17, 2575🔥, 0💬

What are Date and Time Data Types in MySQL
What Are Date and Time Data Types in MySQL? MySQL supports the following date and time data types: DATE - A date in the range of '1000-01-01' and '9999-12-31'. Default DATE format is "YYYY-MM-DD". DATETIME - A date with the time of day in the range of '1000-01-01 00:00:00' and '9999-12-31 23:59:59'....
2018-03-24, 2573🔥, 0💬

Adding a New User Account in MySQL
How To Add a New User Account in MySQL? If you want to add a new user account, you can connect to the server as "root" and use the "CREATE USER ..." command. The command syntax for create a new user account with a specified user name and password is: CREATE USER userName IDENTIFIED BY 'passwordStrin...
2017-09-08, 2572🔥, 0💬

What Do You Think about Oracle SQL Developer in Oracle
What Do You Think about Oracle SQL Developer in Oracle? To conclude this introductory FAQ collection, you should think about Oracle SQL Developer in comparison with other client tools like SQL*Plus and Oracle Web interface. SQL Developer is definitely better than the other tools, more functionality,...
2018-12-26, 2570🔥, 0💬

Sorting Query Output in MySQL
How To Sort the Query Output in MySQL? If you want the returning rows to be sorted, you can specify a sorting expression in the ORDER BY clause. The simplest sort expression is column name who's values will be sorted by. The following select statement returns rows sorted by the values in the "counts...
2017-11-02, 2569🔥, 0💬

What Is a Subquery in MySQL
What Is a Subquery in MySQL? A subquery is a SELECT statement used as part of the selection criteria of the main SELECT statement. The subquery specified in the WHERE clause will be evaluated repeated on each row of the selection base table. The output of the subquery will be used in the final evalu...
2017-09-17, 2569🔥, 0💬

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