HowToDoThings.com Databases

How To Learn MySQL Commands

Daniel452 — Thu, 22 Feb 2007 22:13:00 -0600

A database organizes data so that it can be easily accessed, altered, and managed. Like virtually all database software, MySQL uses Sstructured Query Language (SQL-pronounced sequel), the standard language for requesting information from a database. It is an open-source software, meaning that its free to use and modify for your personal use. Despite it's low price, MySQL has increasingly found wide adoption in industry because of its fast performance, reliability, ease of use, and versatility in working with programming languages. Join the 5 million active users of MySQL including NASA, FedEx and the computer nerd down the block by learning to use the basic asdcommands of MySQL.

How To Use Oracle SQL

miniguru — Thu, 20 Sep 2007 14:31:33 -0500

SQL is shorthand for Structured Query Language. Oracle SQL is a language and not an application. It is a language that can be used to communicate with databases. Oracle SQL can be used to query databases and analyze data.

Before you use Oracle SQL, you need to understand what a database is. What is a database? It’s a collection of data stored in an organized fashion. The data is stored as Tables inside of a database. Data within tables are stored as rows. All data within a database is either a column or a row. Vertical data is called a column, and horizontal data is called a row.

Oracle SQL is composed of keywords such as SELECT, FROM, WHERE, GROUP BY, HAVING, and ORDER BY. The 6 keywords mentioned above allow you to query a database and analyze its data.

When you write a query, please remember to use the SQL keywords below in the order you see them.

How To Convert Access to MySQL

Daniel452 — Mon, 02 Oct 2006 23:44:00 -0500

Both Microsoft Access and MySQL have found wide use in many companies though for different reasons. The main advantage of Access is its relative ease of use while MySQL's strength comes from its versatility. MySQL's versatility allows it to work in conjunction with programs written in various languages as well as even Access. It allows multiple-user access, makes management of large databases easier, provides increased security, and simplifies backup management. In addition MySQL is provided free of charge. To migrate from an Access to MySQL we will be using a free program called DBTools. DBTools has a feature that allows us to directly import data from Access files.

How To Use Structured Query Language (SQL)

kakulz — Mon, 25 Feb 2008 13:49:37 -0600

Structured Query Language (SQL) is a computer language for creating database and manipulating data. SQL is an ANSI (American National Standard Institute) standard and is supported by almost all Relational Data Base Management Systems (RDBMS) like Oracle, MySQL, SQLServer, MS Access, PostGreSQL etc. SQL has two parts:

Data Definition Language (DDL): to create, alter, or drop tables and indexes.
Data Manipulation Language (DML): to insert, update, retrieve or delete the data in the tables.

Here's how to use SQL.

How To Use Formatting in Oracle SQL

miniguru — Thu, 25 Oct 2007 14:20:26 -0500

Once you retrieve your data, you should think about how you would like to view it. You can do a lot of formatting in Oracle SQL, which translates into saved time for you. After all who wants dirty data?

Formatting is a presentation issue. It allows you to present the data you have gathered so that it looks good. And as someone once said, "Perception is key." I use the following 8 formatting tricks. There are many more, but the ones below are essential to know.

How To Add Day, Hour, Minute, Second to a Date Value in Oracle

ndoshi — Mon, 03 Mar 2008 16:46:14 -0600

Date arithmetic is very common in database application. In Oracle, you can add, subtract and compare DATE columns, but you can not multiply or divide it. Oracle stores century, year, month, day, hour, min and seconds as part of the DATE column.

Now let’s take a look at how to add day/hour/minute/second to a date value. Oracle expects a number constant in date arithmetic as number of days. In other words, you need to convert hour, minute and seconds to fraction of a day and then you can add or subtract that value from a date value. Here are some examples:

How To Get Rid of Duplicate Rows in an Oracle SQL Table

ndoshi — Thu, 31 Jan 2008 11:18:09 -0600

If you are using Oracle Database, a common problem is duplicate rows in tables. Usually this happens when unique constraints are removed during loading. Whatever may be the reason, you can remove duplicate records. Duplicate records have identical values for all columns (OR columns that are part of unique key).

There is more than one way to delete duplicate records. Let's assume Table_A has the following data:

Col1 Col2
------ -------
101 201
102 202
103 203
102 202
104 204
101 201

Let's look at the first method.

Selecting Oracle LONG or LONG RAW using ODP.NET in C#

Mon, 18 Apr 2005 20:59:00 -0500

Selecting data using the Oracle Data Provider for .NET (ODP.NET) is quite simple, however, if you forget a simple step, you may end up selecting blank fields for your LONG or LONG RAW's.
As usual, you'll need the proper using clause (or else your code will be overly verbose):using Oracle.DataAccess.Client;using System.Data;Then in your code, simply do:string connstr = "PutYourConnectionStringHere";
OracleConnection conn = new OracleConnection(connstr);
OracleCommand cmd = new OracleCommand("SELECT * FROM MYTABLE", connstr);
// next line says to fetch first 1000 characters of LONG or LONG RAW fields. If you omitted this, it would bring back blank fields instead.
cmd.InitialLONGFetchSize = 1000;
DataSet ds = new DataSet();

Microsoft access cannot start

Peter5 — Wed, 23 Jul 2003 23:00:00 -0500

A solution to the error message "Microsoft access cannot start because there is no license for it on this machine".

I have seen this error arise a few times now. It often occurs after you have installed MS Access. When you try to start access you are presented with the error.

"Microsoft access cannot start because there is no license for it on this machine".

Access then closes.

Strangely enough this problem is caused by a font. To fix the problem follow these instructions.

1) Find the font named Hatten.TTF in your {windows}\fonts folder (usually c:\windows\fonts).

2) Rename the file to Hatten.TTFX

3) Reinstall MS ACCESS

4) Rename the font file back to Hatten.TTF

Access will now start without any problems.

Attach / detatch a database

Peter5 — Tue, 28 Nov 2000 23:00:00 -0600

This article demonstrates how to attach / detatch a database using SQL commands

Open the query analyzer, and enter either

To detatch the database sp_detach_db StuckIndoors

To attach a database sp_attach_single_file_db @dbname = 'StuckIndoors', @physname= 'E:\MSSQLData\data\StuckIndoors.mdf'