Search results
Results from the Health.Zone Content Network
The mysqli_query(), mysqli_real_query() and mysqli_multi_query() functions are used to execute non-prepared statements. At the level of the MySQL Client Server Protocol, the command COM_QUERY and the text protocol are used for statement execution. With the text protocol, the MySQL server converts all data of a result sets into strings before ...
An INSERT statement can also be used to retrieve data from other tables, modify it if necessary and insert it directly into the table. All this is done in a single SQL statement that does not involve any intermediary processing in the client application. A subselect is used instead of the VALUES clause.
PHP provides the mysqli_real_escape_string() function to escape strings according to MySQL semantics; the following example parameterizes a SQL query by escaping username and password parameters: Depending solely on the programmer to diligently escape all query parameters presents inherent risks, given the potential for oversights in the process.
Prepared statement. In database management systems (DBMS), a prepared statement, parameterized statement, or parameterized query is a feature where the database pre-compiles SQL code and stores the results, separating it from data. Benefits of prepared statements are: [1] efficiency, because they can be used repeatedly without re-compiling.
There is also an IGNORE clause for the INSERT statement, which tells the server to ignore "duplicate key" errors and go on (existing rows will not be inserted or updated, but all new rows will be inserted). SQLite's INSERT OR REPLACE INTO works similarly. It also supports REPLACE INTO as an alias for compatibility with MySQL.
Data manipulation language. A data manipulation language ( DML) is a computer programming language used for adding (inserting), deleting, and modifying (updating) data in a database. A DML is often a sublanguage of a broader database language such as SQL, with the DML comprising some of the operators in the language. [1]
A common table expression, or CTE, (in SQL) is a temporary named result set, derived from a simple query and defined within the execution scope of a SELECT, INSERT, UPDATE, or DELETE statement. CTEs can be thought of as alternatives to derived tables , views, and inline user-defined functions.
Structured Query Language ( SQL) ( pronounced S-Q-L; historically "sequel") [4] [5] is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling structured data, i.e., data incorporating relations among entities and variables.