mainframe database types

PL/SQL does not use arrays. Its set data types are similar to those of arrays. In versions earlier than 7.3, there was only one set, called PL/SQL tables. After that, there were two sets of data types: Nested tables and varray. The number of elements in the varray set is limited. The index_by table and the nested table do not have this limit. The index-by table is sparse, that is, the subscript can be disco

This example is used in small projects, want to share to everyone, although simple, but may be useful to everyone.Example: Bookkeeping systemOne:Database: Water records, recorded a lot of consumption types. Such as: The type can be known through the typeID field. (There is a table of consumption types, of course)Two: SQL statement queryDescription: Mainly the use of case statements, according to different c

. Special Data types: Timestamp: timestamp, which is a non-repeating binary number that is automatically generated by the database. uniqueidentifier: Globally unique identifier. Uniquely identifies a row in multiple copies of a table Table: can only be used to define local variables or function return values. XML: Stores XML data. User-defined Types When you crea

Risks of incorrect selection of Oracle Database Design field types, oracle Fields A hidden danger of inaccurate data types. The following constructs a table storage date field, one storage varchar2, and one storage date for a test. I have also written two blogs before: 1. Problems Caused by inconsistent field type design and actual business 1 2. Problems Caused b

self-growth value, once used, is obsolete and will not be reused. 2. Any behavior that adds a value to the self-growing column is incorrect. 3. There are type requirements for columns: int decimal 1. Visualize: In the properties of the column, identify the specification-yes.2. Code: Identity(v) CHECK constraintsThe main thing is to further standardize the values inside the column. 1. Visualize: Right-click the ――check constraint on the column-add a check constraint in the popup dialog box. 2. C

) Double-precision floating-point 16-bit precision (8 bytes) m total number, D decimal place Set a field defined as float (5,3), if you insert a number 123.45678, the actual database is 123.457, but the total number is actually the same, that is, 6 bits. 3. Fixed-point number Floating-point types hold approximate values in the database, while the

(+) not NULL>);You can view show COLUMNS from TB4;(4) Unique constraintThe unique KEY uniqueness constraint guarantees the uniqueness of the record, its fields can be empty (null), and multiple unique constraints can exist for each data table. If you create a data table that has both a primary KEY constraint and a unique constraint:> CREATE TABLE tb5 (> ID SMALLINT UNSIGNED auto_increment PRIMARY KEY,> Username VARCHAR () not NULL UNIQUE KEY,> Age TINYINT UNSIGNED>);You can view show COLUMNS fr

Tags: trim reference a database occupancy build efficiency table structure placeholder BCDIn establishing the database table structure, in order to give a string type of data to define a database type of database, the general reference is char or varchar, summarize the differences between them, clarify the difference b

, Java.sql.Timestamp Timestamp TIMESTAMP Java.util.Calendar Calendar TIMESTAMP Java.util.Calendar Calendar_date DATE Byte[] Binary VARBINARY, BLOB Java.lang.String Text Clob Java.io.Serializable Serializable VARBINARY, BLOB Java.sql.Clob Clob Clob Java.sql.Blob Blob Blob Java.lang.Class Class

What are the five types of integrity constraints? Data constraints based on the MySQL database instance, integrity mysqlTo prevent non-conforming data from entering the database, DBMS automatically monitors the data according to certain constraints when you insert, modify, or delete the data, make the non-compliant data unable to enter the

that you use nvarchar for all fields whose content is stored in Chinese. Operation Description: Open SQL Server Management Studio, select the database for which you want to update the field type, click the new query menu, and execute the following statement. Code details: -- Replace all user data tables in the database with scripts whose field data types are

When establishing the database table structure, in order to give a string type of data to define a database type of database, the general reference is char or varchar, these two choices are sometimes very tangled, today want to summarize the difference between them, and clarify the difference between them. First of all, the length of char is immutable, and the le

Database Tuning tutorial (5) Roles of indexes and types of indexes, tuning IndexesIii. Index In the previous chapter, we learned how to use explain to generate a query execution plan (QEP), so as to discover problems with the statement. Three results returned by explain are related to the index (possible key, key, and extra). It can be seen that the index plays a significant role in improving the query eff

quite a few. ODBCYes. NET Framework1.1New features can be used for other types of databasesODBC. Therefore, the above two connection methods are enhancedSPLMore powerful support for multiple databases. SPL3.0In the previous version2.0Is partially modified.BUGAnd added some new features. SPL3.0RevisedBUG: 1.PairOracleAn error is reported when the database compares dates.OracleThe da

SQLite is especially convenient for storing mobile phone data, but I found some problems during usage: Data Type: Case Insensitive Text Text Numeric Value Integer Integer Real Decimal None No type The above data type is correct. 1. However, if you use other data types such as varchar to create a table, an error occurs. You cannot create a table. 2. If you have used some SQLite table creation tools to create tables, including v

Underlying data type Java type SQL type int or Java.lang.Integer INTEGER Long or Java.lang.Long BIGINT Short or Java.lang.Short SMALLINT float or java.lang.Float FLOAT Double or java.lang.Double DOUBLE Java.math.BigDecimal NUMERIC Java.lang.String VARCHAR byte or Java.lang.Byte TINYINT Boolean or Java.lang.Boolean

:6379> INCR N2#Self-increment(integer) 2 127.0.0.1:6379>INCR n2 (integer)3 127.0.0.1:6379>INCR n2 (integer)4 127.0.0.1:6379> decr N2#Self-reduction(integer) 3 127.0.0.1:6379>decr n2 (integer)2 127.0.0.1:6379> incrbyfloat N2 1.0#self-increment by floating point number "3"127.0.0.1:6379> incrbyfloat N2 1.0"4"127.0.0.1:6379> set N3 4.0 127.0.0.1:6379> incrbyfloat N3 2.1"6.1"127.0.0.1:6379> APPEND N3 2222#Append(integer) 7 127.0.0.1:6379>get N3"6.12222"[END]2017/7/29 16:05:41 View Code Cache

Use Java to access images and other types of files in the MySQL database1. Notes 1. When the database field isBlobType, must usePreparedStatementInSetBinaryStream (int, InputStream, int)Method;2. When the database field isLongblobType, must usePreparedStatementInSetBinaryStream (int, InputStream, long)Method.Otherwise, an error such as the question is thrown:Exce

Tags: and time Retrieve SQL database pos type automatic datatime readabilityDatetimeUsed when you need a value that contains both date and time information. MySQL retrieves and displays the datetime value in ' yyyy-mm-dd HH:MM:SS ' format, supported by ' 1000-01-01 00:00:00 ' to ' 9999-12-31 23:59:59 '. 8 bytes of storage.DATEWhen you need only a date value, there is no time part. MySQL retrieves and displays the date value in ' YYYY-MM-DD ' format, s

Label:--Query database allSELECT (case if A.colorder=1 then d.name else null end) Table name,A.colorder field ordinal, a.name field name,IsNull (G.[value], ") as [description]From Syscolumns ALeft join Systypes B on A.xtype=b.xusertypeINNER JOIN sysobjects D on a.id=d.id and d.xtype= ' U ' and d.nameLeft join syscomments E on a.cdefault=e.idLeft joins Sys.extended_properties G on a.id=g.major_id and a.colid=g.minor_idLeft join Sys.extended_properties