لطفا منتظر باشید ...
P
page
In a virtual storage system, a fixed-length block of contiguous virtual addresses copied as a unit from memory to disk and back during paging operations. SQL Server allocates database space in pages. In SQL Server, a page is 8 kilobytes (KB) in size.
page split
The process of moving half the rows or entries in a full data or index page to two new pages to make room for a new row or index entry.
parent
A member in the next higher level in a hierarchy that is directly related to the current member. The parent value is usually a consolidation of the values of all of its children. For example, in a Time dimension containing the levels Quarter, Month, and Day, Qtr1 is the parent of January.
partition
In Analysis Services, one of the storage containers for data and aggregations of a cube. Every cube contains one or more partitions. For a cube that has multiple partitions, each partition can be stored separately in a different physical location. Each partition can be based on a different data source. Partitions are not visible to users; instead, the cube appears to be a single object.
partitioning
The process of replacing a table with multiple smaller tables. Each smaller table has the same format as the original table but has a subset of the data. Each partitioned table has rows allocated to it based on some characteristic of the data, such as specific key ranges. The rules that define into which table the rows go must be unambiguous. For example, a table is partitioned into two tables. All rows that have primary key values lower than a specified value are allocated to one table, and all keys equal to or greater than the value are allocated to the other. Partitioning can improve application processing speeds and reduce the potential for conflicts in multi-site update replication. You can improve the usability of partitioned tables by creating a view. The view, created by a union of select operations on all the partitioned tables, presents the data as if it all resides in a single table. See also filtering, horizontal partitioning, vertical partitioning.
pass order
The order of evaluation (from highest to lowest calculation pass number) and calculation (from lowest to highest calculation pass number) for calculated members, custom members, custom rollup formulas, and calculated cells in a multidimensional cube. The pass order is used to determine formula precedence when calculating values for cells in multidimensional cubes across all calculation passes. See also solve order.
pass-through query
A query passed un-interpreted to an external server for evaluation. The result set returned by a pass-through query can be used in the FROM clause of a query (like an ordinary base table).
pass-through statement
A SELECT statement that is passed directly to the source database without modification or delay. In PivotTable Service, the PASSTHROUGH option is part of the INSERT_INTO statement.
persistence
The saving of an object definition so that it will be available after the current session ends.
phantom
By one task, the insertion of a new row or the deletion of an existing row in a range of rows previously read by another task that has not yet committed its transaction. The task that has the uncommitted transaction cannot repeat its original read because of the change to the number of rows in the range. If a connection sets its transaction isolation level to serializable, SQL Server uses key-range locking to prevent phantoms.
physical name
The path where a file or a mirrored file is located. The default is the path of the Master.dat file followed by the first eight characters of the file's logical name. For example, if Accounting is the logical name and the Master.dat file is located in Sql\Data, the default physical name is Sql\Data\Accounti.dat. For a mirrored file, the default is the path of the Master.mir file followed by the first eight characters of the mirror file's logical name. For example, if Maccount is the name of the mirrored file and the Master.mir file is located in Sql\Data, the default physical name is Sql\Data\Maccount.mir.
physical reads
A request for a database page in which SQL Server must transfer the requested page from disk to the SQL Server buffer pool. All attempts to read pages are called logical reads. If the page is already in the buffer, there is no associated physical read generated by the logical read. The number of physical reads never exceeds the number of logical reads. In a well-tuned instance of SQL Server, the number of logical reads is typically much higher than the number of physical reads.
pivot
The process of rotating rows to columns and columns to rows in a cross-tabular data browser (to choose dimensions from the set of available dimensions in a multidimensional data structure for display in the rows and columns of a cross-tabular structure).
PK
See primary key (PK).
position
The current location of processing in a cursor. For example, after an application fetches the first 10 rows from a cursor, it is positioned on the 10th row of the cursor. Database application programming interfaces (APIs) also have functions such as the ODBC SQLSetPos function that allow an application to move directly to a specific position in a cursor without performing a fetch.
positioned update
An update, insert, or delete operation performed on a row at the current position of the cursor. The actual change is made in the rows of the base tables used to build the current row in the cursor. Transact-SQL batches, stored procedures, and triggers use the WHERE_CURRENT_OF clause to perform positioned updates. Applications use application programming interface (API) functions such as the ODBC SQLSetPos function to perform positioned updates.
precision
The maximum total number of decimal digits that can be stored (both to the left and right of the decimal point).
prediction
A data mining technique that analyzes existing data and uses the results to predict values of attributes for new records or missing attributes in existing records. For example, you can use existing credit application data to predict the credit risk for a new application. See also decision tree.
prefix characters
A set of one to four bytes that prefix each data field in a native-format bulk-copy data file. The prefix characters record the length of the data value in the field or contain -1 when the value is NULL.
prefix length
The number of prefix characters preceding each non-character field in a bcp native- format data file.
prefix search
Full-text query searching for those columns where the specified character-based text, word, or phrase is the prefix. When using a phrase, each word within the phrase is considered a prefix.
primary dimension table
In a snowflake schema in a data warehouse, a dimension table that is directly related to and is usually joined to the fact table. Additional tables that complete the dimension definition are joined to the primary dimension table instead of to the fact table. See also dimension table, snowflake schema.
primary key (PK)
A column (or set of columns) that uniquely identifies all the rows in a table. Primary keys do not allow null values. No two rows can have the same primary key value; therefore, a primary key value always uniquely identifies a single row. More than one key can uniquely identify rows in a table; each of these keys is called a candidate key. Only one candidate can be chosen as the primary key of a table. All other candidate keys are known as alternate keys. Although tables are not required to have primary keys, it is good practice to define them. In a normalized table, all of the data values in each row are fully dependent on the primary key. For example, in a normalized employee table that has EmployeeID as the primary key, all of the columns should contain data related to a specific employee. This table does not have the column DepartmentName because the name of the department is dependent on a department ID, not on an employee ID.
primary table
The one side of two related tables in a one-to-many relationship. A primary table should have a primary key, and each record should be unique.
private dimension
A dimension created for and used by a specific cube. Unlike shared dimensions, private dimensions are available only to the cube in which they are created. See also shared dimension.
procedure cache
The part of the SQL Server memory pool that is used to store execution plans for Transact-SQL batches, stored procedures, and triggers. Execution plans record the steps that SQL Server must take to produce the results specified by the Transact-SQL statements contained in the batches, stored procedures, or triggers.
process
In a cube, the series of operations that rebuilds the cube's structure, loads data into a multidimensional structure, calculates summaries, and saves the precalculated aggregations. As a verb, process refers to populating a cube with data and aggregations. A verb is one of three processing options for a cube.In a dimension, a process is the operation that loads data from a dimension table in a data warehouse into the levels defined for a dimension and rebuilds the structure of the dimension. The process is one of two processing options for a dimension.In a data mining model, a process is the operation that retrieves training data from a relational or OLAP data source into the structure defined for a data mining model. Statistically, it analyzes it with a data mining algorithm and saves the statistical data as data mining content. As a verb, process refers to populating a data mining model with data mining content. See also incremental update, refresh data.
project
In English Query, a file that contains the structure of the relational database and definitions of semantic objects, such as entities, relationships, and dictionary entries. Its extension is .EQP, and it is used to test how English Query translates English questions into SQL statements. Later, it can be compiled into a deployable application file with an .EQD extension.
property
A named attribute of a control, field, or database object that you set to define one of the object's characteristics (such as size, color, or screen location) or an aspect of its behavior (such as whether it is hidden).
property pages
A tabbed dialog box where you can identify the characteristics of tables, relationships, indexes, constraints, and keys. Every object in a database diagram has a set of properties that determine the definition of a database object. Each set of tabs shows only the properties specific to the selected object. If multiple objects are selected, the property pages show the properties of the first object that you selected.
provider
An OLE DB provider or an in-process dynamic link library (DLL) that provides access to a database.
proximity search
Full-text query searching for those occurrences where the specified words are close to one another.
publication
A publication is a collection of one or more articles from one database. This grouping of multiple articles makes it easier to specify a logically related set of data and database objects that you want to replicate at the same time.
publication database
A database on the Publisher from which data and database objects are marked for replication as part of a publication that is propagated to Subscribers.
publication retention period
A pre-determined length of time that regulates how long subscriptions will receive updates during synchronizations and remain activated in databases.
published data
Data at the Publisher that has been replicated.
Publisher
A server that makes data available for replication to other servers, detects changed data, and maintains information about all publications at the site.
publishing server
An Analysis server that stores the source cube for one or more linked cubes. See also linked cube, subscribing server.
publishing table
The table at the Publisher in which data has been marked for replication and is part of a publication.
Pubs database
A sample database provided with SQL Server.
pull subscription
A subscription created and administered at the Subscriber. Information about the publication and the Subscriber is stored. See also push subscription.
push subscription
A subscription created and administered at the Publisher. Information about the publication and Subscriber is stored. See also pull subscription.
