General MySQL Oracle SQL Server

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What Is View in MySQL
What Is View in MySQL? A view is a logical table defined by a query statement.   ⇒ What Is Join in MySQL ⇐ What Is Index in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-07, 2390🔥, 0💬

What Is Primary key in MySQL
What Is Primary Key in MySQL? A primary key is a single column or multiple columns defined to have unique values that can be used as row identifications.   ⇒ What Is Foreign Key in MySQL ⇐ What Is Row in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-07, 2322🔥, 0💬

What Is Index in MySQL
What Is Index in MySQL? An index is a single column or multiple columns defined to have values pre-sorted to speed up data retrieval speed.   ⇒ What Is View in MySQL ⇐ What Is Foreign Key in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-07, 2288🔥, 0💬

What Is Foreign Key in MySQL
What Is Foreign Key in MySQL? A foreign key is a single column or multiple columns defined to have values that can be mapped to a primary key in another table.   ⇒ What Is Index in MySQL ⇐ What Is Primary key in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-07, 2252🔥, 0💬

What Is ISAM in MySQL
What Is ISAM in MySQL? ISAM (Indexed Sequential Access Method) was developed by IBM to store and retrieve data on secondary storage systems like tapes.   ⇒ What Is MyISAM in MySQL ⇐ What Is Union in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-03, 3959🔥, 0💬

What Is BDB in MySQL
What Is BDB (BerkeleyDB) in MySQL? BDB (BerkeleyDB) is transaction safe storage engine originally developed at U.C. Berkeley. It is now developed by Sleepycat Software, Inc. (an Oracle company now).   ⇒ What Is CSV in MySQL ⇐ What Is InnoDB in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ ... 2017-07-03, 2522🔥, 0💬

What Is MyISAM in MySQL
What Is MyISAM in MySQL? MyISAM is a storage engine used as the default storage engine for MySQL database. MyISAM is based on the ISAM (Indexed Sequential Access Method) concept and offers fast data storage and retrieval. But it is not transaction safe.   ⇒ What Is InnoDB in MySQL ⇐ What Is ISAM in... 2017-07-03, 2491🔥, 0💬

What Is InnoDB in MySQL
What Is InnoDB in MySQL? InnoDB is a transaction safe storage engine developed by Innobase Oy (an Oracle company now).   ⇒ What Is BDB in MySQL ⇐ What Is MyISAM in MySQL ⇑ Database Basics and Terminologies in MySQL ⇑⇑ MySQL Database Tutorials 2017-07-03, 2312🔥, 0💬

Looping through Query Output Rows in MySQL
How To Query Tables and Loop through the Returning Rows in MySQL? The best way to query tables and loop through the returning rows is to run the SELECT statement with the mysql_query() function, catch the returning object as a result set, and loop through the result with the mysql_fetch_assoc() func... 2017-06-28, 8281🔥, 0💬

Quoting Text Values in MySQL
How To Quote Text Values in SQL Statements in MySQL? Text values in SQL statements should be quoted with single quotes ('). If the text value contains a single quote ('), it should be protected by replacing it with two single quotes (''). In SQL language syntax, two single quotes represents one sing... 2017-06-28, 2354🔥, 0💬

Deleting Existing Rows in MySQL
How To Delete Existing Rows in a Table in MySQL? If you want to remove a row from a table, you can use the DELETE statement with a WHERE clause to identify the row. The following sample script deletes one row: &lt;?php include "mysql_connection.php"; $sql = "DELETE FROM fyi_links WHERE id = 1102... 2017-06-28, 2247🔥, 0💬

Dispaly Part Time in Days, Hours and Minutes in MySQL
How To Display a Past Time in Days, Hours and Minutes in MySQL? You have seen a lots of Websites are displaying past times in days, hours and minutes. If you want to do this yourself, you can use the TIMEDIFF() SQL function. Note that the TIMEDIFF() function can only handle time range within 839 hou... 2017-06-23, 3642🔥, 0💬

Query Multiple Tables Jointly in MySQL
How To Query Multiple Tables Jointly in MySQL? If you want to query information stored in multiple tables, you can use the SELECT statement with a WHERE condition to make an inner join. Assuming that you have 3 tables in a forum system: "users" for user profile, "forums" for forums information, and ... 2017-06-23, 3549🔥, 0💬

Key Word Search in Tables in MySQL
How To Perform Key Word Search in Tables in MySQL? The simplest way to perform key word search is to use the SELECT statement with a LIKE operator in the WHERE clause. The LIKE operator allows you to match a text field with a keyword pattern specified as '%keyword%', where (%) represents any number ... 2017-06-23, 2503🔥, 0💬

Quoting Date and Time Values in MySQL
How To Quote Date and Time Values in SQL Statements in MySQL? If you want to provide date and time values in a SQL statement, you should write them in the format of "yyyy-mm-dd hh:mm:ss", and quoted with single quotes ('). The tutorial exercise below shows you two INSERT statements. The first one us... 2017-06-23, 2339🔥, 0💬

Build WHERE Criteria with Web Form Data in MySQL
How To Build WHERE Criteria with Web Form Search Fields in MySQL? If your PHP script is linked to a Web form which takes search key words for multiple data fields. For example, your Web form asks your visitor to search for Website links with a URL search field, a Website title search field, a descri... 2017-06-23, 2320🔥, 0💬

Error: Lock Wait Timeout Exceeded in MySQL
What Happens to Your Transactions When ERROR 1205 Occurred in MySQL? If your transaction receives the "Lock wait timeout exceeded" - ERROR 1205, MySQL server automatically terminates your transaction and rolls back your data changes of the entire transaction. This is why the error messages tells you... 2017-04-28, 5129🔥, 0💬

What Is a Data Lock in MySQL
What Is a Data Lock in MySQL? MySQL uses two types of data locks at two levels to provide you the transaction isolation level you need: Share Lock at Row Level (S) - A data row is locked by a transaction for reading. Exclusive Lock at Row Level (X) - A data row is locked by a transaction for updatin... 2017-04-28, 2451🔥, 0💬

What Is a Dead Lock in MySQL
What Is a Dead Lock in MySQL? A dead lock is phenomenon happens between two transactions with each of them holding a lock that blocks the other transaction as shown in the following diagram: (transaction 1) (transaction 2) update row X to create lock 1 update row Y to create lock 2 update row X (blo... 2017-04-28, 2397🔥, 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, 2353🔥, 0💬

Experiment with Data Locks in MySQL
How To Experiment Data Locks in MySQL? If you want to have some experience with data locks, you can create two windows running two mysql transactions in two sessions. In session 1, you can run a UPDATE statement with REPEATABLE READ transaction isolation level to create an exclusive lock. Before com... 2017-04-28, 2323🔥, 0💬

Turn on and off Autocommit in MySQL
How To Switch between Autocommit-On and Autocommit-Off Modes in MySQL? By default, your connection session will be in Autocommit-On mode, where every server executable statement will start a new transaction, and end the transaction when the execution ends. Changes will be committed. So consider this... 2016-10-17, 2647🔥, 0💬

Ways to Start a New Transaction in MySQL
How To Start a New Transaction in MySQL? MySQL server offers two modes to manage transactions: Autocommit On - Default mode. Can be started with "SET AUTOCOMMIT = 1" command. In this mode, every single SQL statement is a new transaction. All changes will be committed at the end of the statement exec... 2016-10-17, 2636🔥, 0💬

Transaction Committed when START TRANSACTION Executed in MySQL
What Happens to the Current Transaction If a START TRANSACTION Is Executed in MySQL? If you are in a middle of a current transaction, and a START TRANSACTION command is executed, the current transaction will be committed and ended. All the database changes made in the current transaction will become... 2016-10-17, 2427🔥, 0💬

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General MySQL Oracle SQL Server