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Deleting a Table That Is Used by a View in SQL Server
What Happens If You Delete a Table That Is Used by a View in SQL Server? Assuming that you have a table which is used by a view, and you try to delete that table. SQL Server will let you delete the table without any trouble. But that view will become invalid. The tutorial exercise below shows you wh...
2016-11-04, 633👍, 0💬

Determining Data Types of View Columns in SQL Server
How Column Data Types Are Determined in a View in SQL Server? When you define a view, its columns are defined through a list of expressions in the underlying SELECT statement. Their data types will be determined implicitly by the expressions. For example, if the column expression is a column name of...
2016-11-03, 633👍, 0💬

Experiment with Dead Locks in MySQL
How To Experiment Dead Locks in MySQL? If you want to have some experience with dead locks, you can create two windows running two mysql transactions in two sessions at the REPEATABLE READ transaction isolation level. Then run some UPDATE statements as shown in the tutorial exercise below: (session ...
2017-07-21, 632👍, 0💬

UPDATE Using Data from Other Tables in MySQL
How To Use Values from Other Tables in UPDATE Statements in MySQL? If you want to update values in one table with values from another table, you can use a subquery as an expression in the SET clause. The subquery should return only one row for each row in the update table that matches the WHERE clau...
2018-01-13, 631👍, 0💬

Installing SQL Server 2005 Express Edition in SQL Server
How to install SQL Server 2005 Express Edition in SQL Server? Once you have downloaded SQL Server 2005 Express Edition, you should follow this tutorial to install it on your system: 1. Double click SQLEXPR.EXE. The setup window shows up. 2. Click Next to let the setup program to unpack all files fro...
2016-12-08, 631👍, 0💬

Drop an Existing View in Oracle
How To Drop an Existing View in Oracle? If you have an existing view, and you don't want it anymore, you can delete it by using the DROP VIEW statement as shown in the following script: DROP VIEW employee_department; View dropped.   ⇒Understanding SQL DDL Statements for Oracle ⇒⇒Oracle Database Tut...
2020-02-07, 630👍, 0💬

Call a Sub Procedure in Oracle
How To Call a Sub Procedure in Oracle? To call a sub procedure, just use the sub procedure name as a statement. Here is another example of calling a sub procedure: SQL&gt; CREATE OR REPLACE PROCEDURE WELCOME AS 2 PROCEDURE WELCOME_PRINT(S CHAR) AS 3 BEGIN 4 DBMS_OUTPUT.PUT_LINE('Welcome to ' || ...
2018-10-26, 630👍, 0💬

What Is MySQL Server Daemon - mysqld in MySQL
What Is the MySQL Server Daemon - mysqld in MySQL? "mysqld" is MySQL server daemon program which runs quietly in background on your computer system. Invoking "mysqld" will start the MySQL server on your system. Terminating "mysqld" will shutdown the MySQL server. Here is a tutorial example of invoki...
2017-12-09, 630👍, 0💬

Work with Data Objects Interactively in Oracle
How To Work with Data Objects Interactively in Oracle? You can work with data objects through SQL statements in statement area. If you want to work with data objects interactively, you should use the object browser. The following tutorial steps help you to browse data objects: Click the Connetions t...
2018-10-08, 628👍, 0💬

Types of Execution Flow Control Statements in Oracle
What Are the Execution Control Statements in Oracle? PL/SQL supports three groups of execution control statements: IF Statements - Conditionally executes a block of statements. CASE Statements - Selectively executes a block of statements. LOOP Statements - Repeatedly executes a block of statements. ...
2018-11-17, 627👍, 0💬

Using Subqueries in the FROM Clause in SQL Server
How To Use Subqueries in the FROM Clause in SQL Server? If you have a query returning many rows of data, and you want to perform another query on those rows, you can put the first query as a subquery in the FROM clause of the second query. A subquery used in this way become a temporary table, and yo...
2016-10-29, 627👍, 0💬

Improving the Trigger to Handle NULL Values in SQL Server
How To Improve the Trigger to Handle NULL Values in SQL Server? When a NULL value is concatenated with a string, the result will be a null value. So if you want the trigger to properly report NULL values, you need to enhance the trigger as shown in the following tutorial example: USE FyiCenterData; ...
2016-10-24, 627👍, 0💬

"FETCH" - Fetching the Next Row from a Cursor in SQL Server
How To Fetch the Next Row from a Cursor with a "FETCH" Statement in SQL Server Transact-SQL? When the result set is ready in a cursor, you can use a FETCH statement to retrieve one row from the result set in the same format as a SELECT statement. The FETCH statement has the following formats: FETCH ...
2016-10-17, 627👍, 0💬

Query Output Sorted by Multiple Columns in Oracle
Can the Query Output Be Sorted by Multiple Columns in Oracle? 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&gt; SELECT department_id, first_name, last_name, sala...
2019-12-19, 626👍, 0💬

"CREATE DATABASE" Statement - Creating New Databases in SQL Server
How to create new databases with "CREATE DATABASE" statements in SQL Server? This is the first tutorial of a quick lesson on creating database objects with Transact-SQL statements. This lesson shows you how to create a database, create a table in the database, and then access and change the data in ...
2016-12-02, 626👍, 0💬

ONLINE/OFFLINE - Database States in SQL Server
What are database states in SQL Server? A database is always in one specific state. For example, these states include ONLINE, OFFLINE, or SUSPECT. To verify the current state of a database, select the state_desc column in the sys.databases catalog view. The following table defines the database state...
2016-11-20, 626👍, 0💬

CREATE CLUSTERED INDEX - Adding Clustered Indexes in SQL Server
How To Create a Clustered Index in SQL Server? If there is no primary key in a table, you can add one clustered index to that table with CREATE CLUSTERED INDEX statement. The tutorial exercise below shows you how to create a clustered index: USE FyiCenterData; GO -- Drop the old table, if needed DRO...
2016-11-13, 626👍, 0💬

Sorting Query Output with ORDER BY Clauses in SQL Server
How To Sort the Query Output with ORDER BY Clauses in SQL Server? 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 b...
2016-10-26, 626👍, 0💬

What Are DML Statements in MySQL
What Are DML Statements in MySQL? 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 database tables . DELETE - Deleting existing r...
2018-01-24, 625👍, 0💬

NULL Values Involved in String Operations in SQL Server
What Happens If NULL Values Are Involved in String Operations in SQL Server Transact-SQL? If NULL values are involved in string operations, the result will be string NULL values. The following tutorial script shows you some good examples: SELECT 'FyiCenter'+NULL; GO ---------- NULL SELECT LEN(NULL);...
2017-02-05, 625👍, 0💬

"INSERT" and "UPDATE" Statements - Inserting and Updating Data In Tables in SQL Server
How to insert and update data into a table with "INSERT" and "UPDATE" statements in SQL Server? This is the third tutorial of a quick lesson on creating database objects with Transact-SQL statements. This lesson shows you how to create a database, create a table in the database, and then access and ...
2016-12-02, 625👍, 0💬

"DROP DATABASE" - Deleting Databases in SQL Server
How to delete a database in SQL Server? If you created a database incorrectly, or you have a database that is not needed any more, you can delete it with the "DROP DATABASE" statement with this syntax: DROP DATABASE database_name For example, execute this statement: DROP DATABASE FyiCenterData GO Th...
2016-11-24, 625👍, 0💬

Triggers with Multiple Affected Rows in SQL Server
What Happens to a Trigger with Multiple Affected Rows in SQL Server? If there is only one row affected by a DML statement, we know that the DML trigger will be executed once. But how many times the DML trigger will be executed if the DML statement resulted multiple affected rows? The answer is still...
2016-10-24, 625👍, 0💬

"FETCH" - Transferring Data from Cursors to Variables in SQL Server
How To Transfer Data from a Cursor to Variables with a "FETCH" Statement in SQL Server Transact-SQL? By default, a FETCH statement will display the fetched row on the client program window. If you want to transfer the output data to variables, you can specify an INTO clause with a list of variables ...
2016-10-17, 625👍, 0💬

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