forever21 comm

Label:1. Computed ColumnsSELECT * FROM EMP--* indicates that all--from EMP represents the query from the EMP table for select Empno,ename from EMP; Select Ename,sal*12 as "annual salary"From EMP--as can be omitted, remember "annual salary" do not write ' annual salary ', also do not write annual salary,Easy to transplantSelect Ename,sal*12 as "annual salary", Sal "monthly salary", Job from EMP select 5 from EMP; --ok, output a constant value--the number of rows in the output is the number of r

Using System; Using System.Data; Using System.Data.SqlClient; Namespace Sysclasslibrary { Summary description of the DataAccess. public class DataAccess { #region Properties Protected static SqlConnection conn=new SqlConnection (); protected static SqlCommand comm=new SqlCommand (); #endregion Public DataAccess () { Init (); } The DataAccess () constructor is not executed in the static method of #region intrinsic function Open a database connection

asp.net| Access | data using System; Using System.Data; Using System.Data.SqlClient; Namespace Sysclasslibrary { Summary description of the DataAccess. public class DataAccess { #region Properties Protected static SqlConnection conn=new SqlConnection (); protected static SqlCommand comm=new SqlCommand (); #endregion Public DataAccess () { Init (); } The DataAccess () constructor is not executed in the static method of #region intrinsic function Open

Oracle Learning (1): basic syntaxAfter logging on to and installing Oracle with the basic Oracle syntax, enable the Oracle service in services, run cmd, and enter sqlplus scott/Your scott PasswordConnection successful. Screen recording and cleaning SQL> -- screen recording is a txt file SQL> spool off SQL> -- clear screenSQL> host cls Select basic query SQL> -- tables under the current user SQL> select * from tab; TNAME TABTYPE CLUSTERID ----------------------------------------------- DEPT TA

". ConnectionString;SqlConnection objectsprotected static SqlConnection conn = new SqlConnection ();SqlCommand objectsprotected static SqlCommand comm = new SqlCommand ();#endregion #region Internal functionsOpen a database connectionprivate static void ConnectionOpen (){IF (Conn. State!= ConnectionState.Open){Conn. Close ();Conn. ConnectionString = ConnectionString;Comm. Connection = conn;Try{Conn. Open ()

Copy Code code as follows: public class Sqloperation { #region Properties The connection string saved in the web.config protected static string connectionstring = system.configuration.configurationmanager.connectionstrings["Hao". ConnectionString; SqlConnection objects protected static SqlConnection conn = new SqlConnection (); SqlCommand objects protected static SqlCommand comm = new SqlCommand (); #endregion #region Internal functio

database for user query convenience, so dedicated to provide a "dual" virtual table.Example: observing a function that turns uppercaseSELECT UPPER (' Hello ') from dual;sql> SELECT UPPER (' Hello ') from dual; UPPER-----HELLOThe use of uppercase conversions: In general usage, when the user input data to care about the data itself is stored in uppercase and lowercase?SELECT * from emp WHERE ename= ' str ';Sql> SELECT * from emp where ename= ' str '; input str value: Smith original Value 1:se

'); If v_sal Update emp set sal=v_sal+200 where lower (ename) =lower (' name '); dbms_output.put_l INE (' to employees: ' | | ' name ' | | ' Wages increased by 200. '); End If; End; 2.2 Binary Conditional branching Syntax 2: If logical expression 1 then Statement 1; else Statement 2; End If; Example 1: Declare v_sal number; V_avg number; Begin Select AVG (SAL) into the v_avg from EMP; Select Sal to v_sal from EMP where empno=7788; If V_sal>v_avg Then Dbms_output.put_line ('

string in Java?---java and string concatenation, it really spelled a null---package Oracle;--public class Demo {--public static void main (String[]args) {--String Str=null;--System.out.println ("str:" +STR);--}--}--->str:null---and numeric operations, the result is still null.---View each employee's income (Payroll plus performance)SELECT ename,sal,comm,sal+comm from EMP_RR;---null value function---1.NVL (

Ado|web four, Command object: As you can see from the literal meaning of English, command is used to perform commands and parameter passing. The command object's bulk parameter transmission, storedprocude execution, and so on flexible and powerful function is also the reason that it is favored. The command object is primarily about passing parameters to SQL statements, Storedprocude, and relying on the powerful capabilities of SQL Server to complete the operation of the database, and the Records

Common Oracle functions: nvl/nullif/case when/wm_concat/replace 1. nvl function nvl converts a null value to an actual value. The data type can be date, number, character, and data type must match: nvl (commision, 0) nvl (hiredate, '01-JAN-87 ') nvl (job_id, 'no manager') nvl (to_char (job_id), 'no manager') nvl can convert any data type, however, the returned value of the converted data type must be of the expr type of the first parameter nvl (expr1, expr2. example: date, number, varchar2 or ch

stored procedure to delete a topic'Back: NO'By king'================================================ ====================Function Fun_delete_column (DelScope, Site_id, column_id)'Create proc pro_delte_column'@ Del_scope varchar (100 ),'@ Site_ID int,'@ COLUMN_ID int,'@ Back_message varchar (100) output'Establish a database connectionSet Comm = Server. CreateObject ("ADODB. Command ")Comm. ActiveConnection

From: http://www.lemongtree.com/2006/11/28/0000572.aspxA friend on csdn asked this question and wrote it later. Why do we need to customize it?First, customization is more flexible and does not rely too much on the aspnetdb database, which facilitates your own expansion. Second, you can still use the login control in. NET 2.0 after customization.Of course, custom is not customized at will, but two abstract classes are implemented:Membershipprovider and roleproviderFor more information about th

ADO. An overview of the 5 large objects in net :1---Connection object : Connect to the database.(1) Log in with SAconn = new SqlConnection ("Data source=newland-pc;initial catalog=srr1100u; User id=sa;pwd=123456; " ); Conn. Open (); (2) using Windows Local Login New SqlConnection ("Data source=newland-pc;initial catalog=image;integrated security=true;" 2---Command object : Executes the T-SQL statement.(1) ExecuteNonQuery () method, perform additions and deletions to change the command.

compare to the relationship value and instead to the exist () with Sql:column ().Http://msdn.microsoft.com/zh-cn/library/ms178030.aspxImplemented using the XML value method (not recommended) Copy Code code as follows: DataTable dt = new DataTable (); using (SqlConnection conn = new SqlConnection (connectionString)) { string xml = @ " SqlCommand COMM = conn. CreateCommand (); Using the value method is not recommended, and performance

column Name 1, column name 2,..., column name n from table name;Exercise: Select Empno,ename,sal,comm,deptno from EMP;3.3 Queries show the Dept Department: Department number, department name, areaSelect Deptno,dname,loc from dept; --"Summary" FROM clause-------------------------------------------------------------------------------------Query all fields of a table: field names are available * instead. Select Column Name 1, column Name 2, ..., column

I. SQL trigger sending Ii. Send the winform program with the task plan Page // ReferenceUsing System. Data. Common;Using System. Data. SqlClient;Using System. Configuration;Using System. Data;Using System. Net. Mail; // The email to be sentPublic static DataSet SendEmailList (){DataSet ds = new DataSet ();Try{String str = ConfigurationSettings. etettings ["ConnectionString"];SqlConnection conn = new SqlConnection (str );Conn. Open ();SqlCommand comm

connectionSqlconnection conn = new sqlconnection (sqlconnstring );Try{Conn. open ();}Catch (exception E){// Record the cause if the connection failsEventLog. writeentry (E. Message );Return;}// Start the transactionSqltransaction TRAN = conn. begintransaction ();Sqlcommand comm = new sqlcommand (); Comm. Transaction = Tran;Comm. Connection = conn;Try{// Obtain t

; } returnConn; } } /// ///Create command/// /// /// /// /// Public StaticDbCommand CreateCommand (stringSQL, CommandType commandtype,paramsdbparameter[] sqlparams) {DbCommand Comm=db. CreateCommand (); Comm. Connection=Conn; Comm.commandtype=CommandType; Comm.commandtext=SQL; if(Sqlparams! =NULL) {

Oracle analysis function PERCENTILE_CONT Query the salaries of people with the salary distribution of 25%, 50%, and 75% in each department. percent_rank () is the relative position in the ranking. Create table EMP (empno number (4) not null, ENAME VARCHAR2 (10), JOB VARCHAR2 (9), mgr number (4), hiredate date, sal number (7, 2 ), comm number (7369), deptno number (2); insert into emp (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL,