two types of database

In the forum, there will be different types of posts, such as: General paste, essence, top posts;These posts in the Forum are sorted according to the different types, not just the type of posts, but also the dynamics of the postings.Here's a simple sort of post, and we're just looking at the latest dynamic time of the post and the sort of post type.The latest dynamic time is determined: if you just created

stream of characters to output the sound.Long string types are not commonly used. Personal privacy, voice, image, computer was lost, to repair the computer is also OK. //------------------------------------------------------------------------------------------------------------- -----Three. Date and Time typeDate only recorded on 2015-01-14Time is only recorded 11:36:25Year Only records years 2015Datatime record date and record time 2015-01

: Integer data from 0 to 255.Bit:1 or 0 of integer data.(4) decimal and numericBoth of these data types are equivalent. have two parameters: P (Precision) and S (decimal digits). p Specifies the maximum number of decimal digits that can be stored to the left and right of the decimal point, and P must be a value from 1 to 38. s specifies the maximum number of decimal digits that can be stored to the right of the decimal point, s must be a value from 0

, with a decimal point followed by 307 zeros. The storage space occupied by float and double types is 4 bytes and 8 bytes respectively. If you need to use decimal fields, the precision is not high, of course, float is used! But to be honest, how does our "Civil" data require high accuracy? I have never used these two types so far-I have not encountered any examples that are suitable for using them. The most

about 2.22E-308 (0.000 ...). 0222, the decimal number of 307 0 after the decimal point. The float type and double type occupy storage space of 4 bytes and 8 bytes respectively. If you need to use a decimal field, the precision is not high, of course, with float! But to say the truth, we "civil" data, which has the requirement of precision so high? These two types have not been used so far-I have not yet encountered cases that are appropriate for usin

Key-Value Store databaseTemporary: as memcached. The temporary key-value database stores the data in memory, which in two cases results in the loss of data, the first is the power outage, but the data content exceeds the memory size. The benefits of this treatment are very fast.Permanent type: such as Tokyo Tyrant, flare and RomaThe two are both types: Redis. Redis first data in memory, and then meet certai

The following articles mainly introduce three different types of JDBC drivers in Oracle databases. We all know that jdbc drivers in Oracle mainly include the following three types: 1. jdbc oci: oci is the abbreviation of Oracle call interface, which is similar to the traditional ODBC driver. Because it requires Oracle Call Interface and Net8, it needs to install the client software on the machine that runs

Data type:Integer type: bigint, int, smallint, mediumint, tinyintDecimal type: decimal, numericFloat type: Real, float, doubleBit type: bitCharacter type: char, varchar, LongVarChar, longtextUnicode character type: nchar, nvarcharTextual: Text, TinytextBinary type: binary, varbinaryDateTime type: Date, time, DateTime, timestamp, yearThe Datetime range is: 1753.1.1--9999.12.31smalldatetime range is: 1900.1.1--2079.6.6Create a database: Right-click the

versionand Ord (Mid (Version (), plus)) >51 Normal is 4.0 above 51 is ASC code 3To determine the number of fields in the current database1 UNION limit requires two statements to have the same number of fields2 Order by Number return field number//field refers to the column of the data table, the record refers to the row of the data tableand 1=2 Union statement can burst the position of these numbersAfter you know the number of fields, we can use the union query to get the table name of the curr

Summary: This paper discusses the method and function realization of using ASP to access DBF, DBC, MDB, Excel, SQL Server data, and finally gives an example of accessing Excel database by using the function provided in this paper, which has strong practical meaning for enterprise data reuse and sharing. Keywords: ASP database access, Dbf,dbc,mdb,excel,sql Server Objective The Internet/intranet Web pages are

Since 08, after learning SQL Server database, it has been thought that SQL Server only version of the distinction, no type of difference; always think from Sql2000, sql2005 to sql2008, sql2012, Microsoft Export database, only version upgrade, There's nothing else. In fact, the database we use most often is described as follows:I. SQL Server ExpressThis

The following articles mainly introduce the time types of MySQL Databases and Java databases. The following articles mainly describe the time types corresponding to the time types in MySQL Databases and Java databases, the following is a detailed description of the article. I hope you will gain some benefits after browsing it. The time

The data types and sizes in database storage vary. In some cases, only the numeric type is stored, and some only the text type is stored. Many databases support various specialized types: Date and Time, binary character, and Boolean. Matching data types with data is the most important part in

supported where integer values are supported. However, bigint is used in some special cases. When the integer value exceeds the range supported by the int data type, bigint can be used. In SQL Server, the int data type is the main integer data type.In the data type precedence table, bigint is located between smallmoney and int.The function returns bigint only when the parameter expression is of the bigint data type. SQL Server does not automatically upgrade other integer data

modification data does not affect another transaction, even if the modified transaction has been committed and does not affect the other transaction. Therefore, the isolation level does not appear to be non-repeatable to read. However, Phantom reads appear at this level. Phantom reads : A phenomenon that occurs when a transaction is not executed independently, such as when the first transaction modifies data in a table that involves all rows of data in the table. At the same time, the second tr

. Encode and read images and text filesCodeImport Java.sql.*;import java.io.*;p ublic class getconnection{public static void Main (string[] args) {access2database Adb=new access2database (); Connection conn=adb.getconn ();//transaction dealingpreparedstatement Pstam=null; String sql= "SELECT * from Stuinfo where name=?;"; try {pstam=conn.preparestatement (SQL);p stam.setstring (1, "CJC"); ResultSet Reset=pstam.executequery (); while (Reset.next ()) {System.out.println ("Read text Document ...");

There are several types of strings defined in the database: Char, varchar, and nvarchar. The three types are different. CHAR: The length of the char type is fixed and the maximum length is 2000 characters. When a field is assigned a value, if the length of the string is smaller than the defined char type, the system automatically fills in the null value. When t

index on both columns (A, b), and only A is used in the WHERE clause, the index will not work.• The hash index only supports equality comparisons that use = in (). They cannot speed up the range query. For example where price > 100;• Accessing data in a hash index is very fast, unless the collision rate is high. When a collision occurs, the storage engine must access each row pointer in the linked list and then row-by-line data comparison to determine the correct data. If there are many collisi

If you are new to the DB2 database, you need to know the log types in the DB2 database. The following describes the log types in the DB2 database for your reference, hope to help you. 1. Log Type 1.1 Activity log active log) This function is similar to ORACLE's online red

")--Create the MyDB log file and place it on the E disk.4. Open the DatabaseUse MyDBUse master5. Modify the dataALTER DATABASE MyDB--Modify MyDB databasesAdd file--adding file files(Name= "MyDB2",--Create a secondary data file called MyDB1.Filename= "C:\MYDB2.NDF"--Place the MyDB data file in the C drive.)6. Deleting a databaseDrop Database MyDB7. View the database