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The returned query results can also be checked strictly. Preprocessor might generate static SQL which performs better than dynamic SQL because query plan is created on program compile time, stored in database and reused at runtime. Static SQL can guarantee access plan stability. IBM DB2 supports static SQL use in SQLJ programs.
Major DBMSs, including SQLite, [5] MySQL, [6] Oracle, [7] IBM Db2, [8] Microsoft SQL Server [9] and PostgreSQL [10] support prepared statements. Prepared statements are normally executed through a non-SQL binary protocol for efficiency and protection from SQL injection, but with some DBMSs such as MySQL prepared statements are also available using a SQL syntax for debugging purposes.
However, if the "userName" variable is crafted in a specific way by a malicious user, the SQL statement may do more than the code author intended. For example, setting the "userName" variable as: ' OR '1'='1. or using comments to even block the rest of the query (there are three types of SQL comments [8]). All three lines have a space at the end:
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
E. F. Codd mentioned nulls as a method of representing missing data in the relational model in a 1975 paper in the FDT Bulletin of ACM-SIGMOD.Codd's paper that is most commonly cited with the semantics of Null (as adopted in SQL) is his 1979 paper in the ACM Transactions on Database Systems, in which he also introduced his Relational Model/Tasmania, although much of the other proposals from ...
push 1L (the number one with type long) onto the stack ldc 12 0001 0010 1: index → value push a constant #index from a constant pool (String, int, float, Class, java.lang.invoke.MethodType, java.lang.invoke.MethodHandle, or a dynamically-computed constant) onto the stack ldc_w 13 0001 0011 2: indexbyte1, indexbyte2 → value
interface StringManipulator {String extendString (String input); // A method which is optional to implement default String shortenString (String input) {return input. substring (1);}} // This is a valid class despite not implementing all the methods class PartialStringManipulator implements StringManipulator {@Override public String ...
SQL:2016 or ISO/IEC 9075:2016 (under the general title "Information technology – Database languages – SQL") is the eighth revision of the ISO (1987) and ANSI (1986) standard for the SQL database query language. It was formally adopted in December 2016. [1] The standard consists of 9 parts which are described in some detail in SQL.