Programming Visual Basic - Free Download : PDF - Price, Reviews - IT Books
· Chapter 4. Designing the Database Data. Databases. It just kind of makes sense. If you have data, you need to put it somewhere. And what better place to put it - Selection from Programming Visual Basic [Book]. Ever since Visual Basic was merged blogger.com, it's become the core language for creating business applications with Windows. The latest version, VB , is even more useful -- and provides even more incentive for migrating from VB 6. All it lacks is a good book on how to harness its power. Programming Visual Basic fills the void. Written in a lively and engaging style by a developer who 3/5(13). 图书标签: VB6 VB 喜欢 Programming Visual Basic 的读者还喜欢 Programming Visual Basic pdf epub mobi txt 下载 图书描述 Ever since Visual Basic was merged blogger.com, it's become the core language for creating business applications with Windows. The latest version, VB , is even more useful - and.
9780596518431 pdf download
It just kind of makes sense. If you have data, you need to put it somewhere. What a shock. All my disk files are organized for easy access. My saved emails can be sorted by subject or date received or sender, so they must be in a database, too. Even this document can be searched and sorted in 9780596518431 pdf download manner I wish. Is it a database? Perhaps that definition is too broad. The relational databases that most programmers use collect data in tableseach of which stores a specific set of unordered records.
For convenience, tables are presented as a grid of data values, with each row representing a single record and each column representing a consistent field that appears in each record. Putting all of your information in a table is really convenient. Unfortunately, this table of orders has a lot of repetition. Customer names and product names repeat multiple times. Codd, the brilliant computer scientist that he was, saw these problems, too. But instead of just sitting around and complaining about them like I do, he came up with a solution: normalization.
To get combined results from multiple tables at once, 9780596518431 pdf download, join or link their matching fields. For instance, you can link the Customer ID field in the table of line items with the matching Customer ID primary key field in the table of customers. Once joined, the details for a single combined line item record can be presented with the matching full customer name.
To join tables together, relational databases implement query languages that allow you to manipulate the data using relational algebra from which the term relational database derives. The most 9780596518431 pdf download of these languages, SQL, uses simple English-like sentences to join, order, 9780596518431 pdf download, summarize, and retrieve just the data values you need. SQL also includes data definition language DDL statements that let you design the tables used to hold the data, as well as other database features, 9780596518431 pdf download.
They also battle one another over 9780596518431 pdf download features such as data replication, 9780596518431 pdf download, crash-proof data integrity, the speed at which complex queries return the requested results, and who has the biggest private jet. Although it began its life as a derivative of Sybase another relational databaseit has been given the Microsoft touch.
Although Microsoft was somewhat late in joining the relational database game, it has done a pretty good job at playing catch-up. Oracle still gets high marks for at least its perception of being the most robust, the most stable, and the most platform-independent of the various players. But SQL Server scores big as well, especially with its 9780596518431 pdf download lower costs and its more intuitive visual tools. Originally, Microsoft touted SQL Server as a business-minded tool for business-minded people with their business-minded agendas and their business-minded three-piece poly-knit double-breasted suits, and it is still viewed in this way.
But Microsoft is increasingly identifying the database as a development tool, especially with the release. Microsoft announced the release of 9780596518431 pdf download Serverthe latest version of its star database product, in tandem with Visual Studio However, although the two products share a common launch date, 9780596518431 pdf download, the actual availability dates of the two products are months apart, with SQL Server coming out after Visual Studio.
If you choose to use the version of the product, you should have no difficulties in following the discussion in this book. It runs in the background on a system and communicates with 9780596518431 pdf download, the user, 9780596518431 pdf download, by having you first establish a standard network connection with the server engine.
This is true even if the SQL Server engine runs on your own workstation. Watching a server product is about as exciting as reading some of those other Visual Basic tutorial books that you wisely avoided, so Microsoft provides various client tools that let you manage databases, tables, and other relational database properties.
This only impacts the few times when I refer specifically to the client tools. Although Microsoft continues to update and sell Microsoft Access, it is recommending more and more that professional developers use and distribute databases in SQL Server format.
Conducting business in Japan is pretty easy—once you know the language. Well, kind of. The core parts of the SQL language are pretty consistent between vendors, but each supplier adds a lot of extra features and syntax variations designed by Edgar Codd wannabes.
Traditional SQL code is mostly uppercase. I use uppercase for 9780596518431 pdf download keywords, and mixed case for tables, fields, and other custom items.
Whatever you choose, consistency is important. Also, employ whitespace as you see fit. You can put statements on one gigantic line, or put every word on a separate line. SQL statements normally end with a semicolon, but some tools do not require you to include the semicolon, and other tools require that you exclude it. SQL statements used in Visual Basic code never include semicolons. This may come as a shock to you, but before you can store any data in a table, you have to create that table.
9780596518431 pdf download basic syntax is pretty straightforward:. Table and field names are built from letters and digits; you can include spaces and some other special characters, but it makes for difficult coding later on.
Extensions to the syntax let you set up constraints that apply to the entire table, indexes which let you sort or search a specific column more quicklyand data storage specifics. The bigint and smallint data types indicate appropriately sized integer fields, and the varchar type provides space for text, up to the maximum length specified in the parentheses 20 characters.
CustomerID field match the key values from 9780596518431 pdf download Customers. CustomerID field. It shows up everywhere in SQL. References between tables are also known as foreign references.
You might want to avoid this statement on live production data, as users tend to get a bit irritable when their data suddenly disappears off the surface of the earth. Fixed-length binary data, up to 8, bytes in length. You specify the length through a parameter, as in 9780596518431 pdf download Supports three possible values: 10or NULL. Generally used for Boolean values. Internally, SQL Server stores multiple bit fields from a single record in a merged integer field.
Fixed-length standard char or Unicode nchar strings, up to 8, characters in length. You specify the length through a parameter, as in char Time accuracy for any given value is within 3. SQL Server adds several new date-related data types: date dates without timestime times without datesdatetime2 same as datetimebut with a larger range and accurate to nanosecondsand datetimeoffset date and time ranges.
A fixed-precision and scale decimal field. You specify the maximum number of digits to appear on both sides of the decimal point the precision and the maximum number of those digits that can appear on the right side of the decimal point the scale. For instance, a setting of decimal 10,4 creates a field with up to 10 total digits, four of which may appear after the decimal point.
The maximum precision value is A floating-point decimal field with variable storage. You can specify the number of bits used to store the value, up to By default, all 53 bits are used, so a setting of float is equivalent to float The pseudodata type real is equivalent to float This data type is susceptible to minor calculation errors.
This data type, new with SQL Serversupports querying of hierarchical and tree-shaped data, 9780596518431 pdf download. It is not available in SQL Server An 8-byte bit high-accuracy field 9780596518431 pdf download storing currency values, with up to four digits after the decimal point. This data type is used to 9780596518431 pdf download modification events on records. There are restrictions on its use, and it is not guaranteed to be unique within a table.
Time accuracy for any given value is within one minute. A 4-byte bit high-accuracy field for storing currency values, with up to four digits after the decimal point, 9780596518431 pdf download. A special field that temporarily stores the results of a query in a compacted table format. Defining a table field is somewhat complex, and its use naturally carries with it certain restrictions.
A byte globally unique identifier GUID. Variable-length binary data, up to 8, bytes in length. You specify the length through a parameter, as in varbinary The field only consumes space for the actual content currently stored in the field. A special setting of varbinary max allows entry of 9780596518431 pdf download to about 2 billion bytes. Variable-length standard varchar or Unicode nvarchar strings, up to 8, characters in length.
You specify the length through a parameter, as in varchar A special setting of varchar max allows entry of up to about 2 billion characters, 9780596518431 pdf download. The DML statements are more useful for everyday data surfing. Data is added to a table one record at a time. A variation of 9780596518431 pdf download lets you insert multiple records, but those records must come from another existing table source, 9780596518431 pdf download.
To use the INSERT statement, specify the 9780596518431 pdf download table and fields, and then the individual values to put into each field. One data value corresponds to each specified data column name. SQL Server also does a variety of data integrity checks on your behalf. Each data field you add must be of the right data type, but you already expected that. Since we designed the CustomerID field to be a reference to the Customer table, the insert will fail if customer BW3 does not already exist in the Customer table.
9780596518431 pdf download
· Chapter 4. Designing the Database Data. Databases. It just kind of makes sense. If you have data, you need to put it somewhere. And what better place to put it - Selection from Programming Visual Basic [Book]. 图书标签: VB6 VB 喜欢 Programming Visual Basic 的读者还喜欢 Programming Visual Basic pdf epub mobi txt 下载 图书描述 Ever since Visual Basic was merged blogger.com, it's become the core language for creating business applications with Windows. The latest version, VB , is even more useful - and. Programming Visual Basic PDF Download Free | Tim Patrick | O'Reilly Media | | | MB | blogger.com Applications with Microsoft's RAD Tool for Business.
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