tablespace is a logical storage container for segments. Segments are database objects, such as tables and indexes, that consume storage space.
segment is a set of extents allocated for a specific database object, such as a table. Each segment belongs to one and only one tablespace.
extent is a set of logically contiguous data blocks allocated for storing a specific type of information.
logical data block corresponds to a specific number of bytes of physical disk space, for example, 2 KB.
ALTER USER hr ACCOUNT UNLOCK; ALTER USER hr IDENTIFIED BY hr_password;
CREATE TABLE "HR"."COUNTRIES" ( "COUNTRY_ID" CHAR(2 BYTE) CONSTRAINT "COUNTRY_ID_NN" NOT NULL ENABLE,
"COUNTRY_NAME" VARCHAR2(40 BYTE), "REGION_ID" NUMBER, CONSTRAINT "COUNTRY_C_ID_PK" PRIMARY KEY ("COUNTRY_ID") ENABLE, CONSTRAINT "COUNTR_REG_FK" FOREIGN KEY ("REGION_ID")
REFERENCES "HR"."REGIONS" ("REGION_ID") ENABLE
) ORGANIZATION INDEX -- index-organized table.
ORGANIZATION: the order in which the data rows of the table are stored.
- HEAP: the data rows of table are stored in no particular order. This is the default.
- INDEX: table is created as an index-organized table. In an index-organized table, the data rows are held in an index defined on the primary key for the table.
EXTERNAL: table is a read-only table located outside the database.
NOCOMPRESS -- whether to compress data segments to reduce disk use PCTFREE 10 -- NOCOMPRESS use the PCTFREE default value of 10, to maximize compress while still allowing for some future DML changes to the data INITRANS 2 -- Specify the initial number of concurrent transaction entries allocated within each data block allocated to the database object. MAXTRANS 255 -- deprecated. LOGGING -- a database object will be logged in the redo log file
STORAGE( INITIAL 65536 -- the size of the first extent of the object. allocates space when you create the schema object. NEXT 1048576 -- in bytes the size of the next extent to be allocated to the object. MINEXTENTS 1 -- In locally managed tablespaces, determine the initial segment size in conjunction with PCTINCREASE, INITIAL and NEXT MAXEXTENTS 2147483645 -- valid only for objects in dictionary-managed tablespaces PCTINCREASE 0 -- Oracle recommends a setting of 0 as a way to minimize fragmentation and avoid the possibility of very large temporary segments during processing. FREELISTS 1 -- each free list group contains one free list FREELIST GROUPS 1 -- In tablespaces with manual segment-space management, statically partition the segment free space in an Oracle Real Application Clusters environment. BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT )
TABLESPACE "USERS" PCTTHRESHOLD 50; -- when an overflow segment is being used, defines the maximum size of the portion of the row that is stored in the index block, as a percentage of block size. 1–50. The default is 50.
CREATE PROCEDURE find_root ( x IN REAL ) IS LANGUAGE C
Use the call_spec to map a Java or C method name, parameter types, and return type to their SQL counterparts.
NAME c_find_root LIBRARY c_utils PARAMETERS ( x BY REFERENCE );
create or replace PROCEDURE add_job_history ( p_emp_id job_history.employee_id%type , p_start_date job_history.start_date%type , p_end_date job_history.end_date%type , p_job_id job_history.job_id%type , p_department_id job_history.department_id%type ) IS BEGIN INSERT INTO job_history (employee_id, start_date, end_date, job_id, department_id) VALUES(p_emp_id, p_start_date, p_end_date, p_job_id, p_department_id); END add_job_history;