barcode generator in vb.net code project SQL Syntax Conventions in Software

Printer PDF417 in Software SQL Syntax Conventions

SQL Syntax Conventions
Recognizing PDF-417 2d Barcode In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
PDF417 Generator In None
Using Barcode creator for Software Control to generate, create PDF417 image in Software applications.
This section presents the general syntax conventions used in forming SQL statements. However, keep in mind that there are a lot of vendor extensions and variations. For simplicity, the term implementation is used to refer to each version of SQL from each vendor (that is, Oracle 9i, Oracle 10g, Microsoft SQL Server 7, Microsoft SQL Server 2000, and Microsoft SQL Server 2005 all contain different implementations of SQL). SQL syntax conventions will be easier to understand using a simple example. This statement lists the Movie ID and Movie Title for every movie in the video store that has a rating of PG:
PDF 417 Decoder In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
Print PDF 417 In Visual C#
Using Barcode printer for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in .NET framework applications.
SELECT MOVIE_ID, MOVIE_TITLE FROM MOVIE WHERE MPAA_RATING_CODE = 'PG';
Create PDF417 In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create PDF417 image in ASP.NET applications.
Create PDF 417 In .NET Framework
Using Barcode drawer for .NET Control to generate, create PDF-417 2d barcode image in Visual Studio .NET applications.
CHAPTER 2 SQL Concepts
Printing PDF 417 In VB.NET
Using Barcode generator for .NET Control to generate, create PDF 417 image in .NET applications.
EAN13 Encoder In None
Using Barcode creator for Software Control to generate, create EAN-13 image in Software applications.
The basic conventions are Each statement begins with a command, usually in the form of a single word, which is almost always an action verb. In this example, the statement starts with the SELECT command, which is described in detail in 4. Each statement ends with a delimiter, which is usually a semicolon (;). Some implementations allow the delimiter to be changed to some other character. Moreover, some implementations such as Oracle s will not execute an SQL statement that is missing the ending delimiter, while other implementations consider the ending delimiter optional. Statements are formed in a similar manner to English sentences, with one or more spaces used to separate language elements. A language element, similar to a word in an English sentence, is any keyword (SELECT, FROM, WHERE), database object name (MOVIE, MOVIE_ID, MOVIE_TITLE), operator (=), or constant ( PG ) that may appear in a statement. Statements are written in a free-form style, which means there are no strict rules about the position of language elements on a line or where a statement may be broken to a new line. However, it is generally not a good idea to split any single language element across multiple lines. This statement is logically identical to the one shown at the beginning of this topic, but isn t as easy to read and understand:
Code 128 Drawer In None
Using Barcode creator for Software Control to generate, create Code 128 Code Set B image in Software applications.
Data Matrix ECC200 Maker In None
Using Barcode generator for Software Control to generate, create DataMatrix image in Software applications.
SELECT MOVIE_ID,MOVIE_NAME FROM MOVIE WHERE MPAA_RATING_CODE='PG';
Encode UPC-A In None
Using Barcode creation for Software Control to generate, create UPC A image in Software applications.
Code 3/9 Generator In None
Using Barcode drawer for Software Control to generate, create Code39 image in Software applications.
Statements are organized into a series of clauses, and usually clauses must appear in a particular sequence when they are present (many clauses are optional). In our example, there are three clauses, each beginning with a keyword (SELECT, FROM, WHERE). SQL language elements may be written in upper- or lowercase or mixed case. However, in most implementations, and per the ANSI/ISO standards, all lowercase characters are automatically shifted to uppercase for processing. This is not to say that data can never be in lowercase but rather that commands and database object names (tables, columns, etc.) must be in uppercase. Notable exceptions are Microsoft SQL Server and Sybase, both of which allow the database to operate in case-sensitive mode wherein object names written in different cases are treated as different names. In MySQL, object name case sensitivity is tied to whether or not the underlying operating system has case-sensitive names or not.
Create RoyalMail4SCC In None
Using Barcode encoder for Software Control to generate, create British Royal Mail 4-State Customer Barcode image in Software applications.
Matrix Barcode Creator In Visual Studio .NET
Using Barcode drawer for .NET framework Control to generate, create 2D Barcode image in .NET applications.
SQL Demysti ed
Creating Barcode In .NET Framework
Using Barcode encoder for Reporting Service Control to generate, create bar code image in Reporting Service applications.
Make Code 128 Code Set C In Visual Studio .NET
Using Barcode printer for ASP.NET Control to generate, create Code 128C image in ASP.NET applications.
Commas are used to separate items in a list. In our example, two column names were provided in a comma-separated list (MOVIE_ID, MOVIE_ TITLE). Spaces following each comma are completely optional you can include no spaces, or as many as you want. Character strings that appear in SQL statements must be enclosed in single quotes (some SQL implementations also allow double quotes). Numeric constants are never enclosed in quotes. If a quote needs to appear within the character string, two single quotes next to each other take care of it. For example, if you wanted to nd the movie Sophie s Choice in the database, you would write the WHERE clause like this:
Printing ECC200 In Visual C#
Using Barcode generation for VS .NET Control to generate, create ECC200 image in VS .NET applications.
Universal Product Code Version A Recognizer In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
WHERE MOVIE_NAME = 'Sophie''s Choice'
Read ANSI/AIM Code 39 In Visual C#
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in VS .NET applications.
Encode Data Matrix In Java
Using Barcode encoder for Eclipse BIRT Control to generate, create DataMatrix image in Eclipse BIRT applications.
Database object names are formed using only letters, numbers, and the underscore character. Underscores are typically used as separators between words to improve readability. As previously mentioned, some implementations allow case-sensitive names such as PersonMiddleName, a style often called camelcase, but this is not a good practice if the SQL is to be portable to other implementations. After all, a name like PERSONMIDDLENAME is not very easy to read. Each SQL implementation has a de ned set of reserved words, which are words that have speci c meaning to the SQL query processor in the DBMS and therefore may not be used in other contexts, such as for the name of database objects. This restriction is to avoid misinterpretation of SQL statements by the DBMS. As you might guess, the list of reserved words varies signi cantly from one SQL implementation to another, so it is wise to consult the documentation for the implementation you are using to become familiar with them. A single-line comment is started with two consecutive hyphens (--). The two hyphens can be at the beginning of a line, in which case the entire line becomes a comment, or elsewhere in the line, in which case the remainder of the line is treated as a comment. For example:
Copyright © OnBarcode.com . All rights reserved.